diff options
| -rw-r--r-- | kernel/module.c | 9 | ||||
| -rw-r--r-- | kernel/params.c | 4 | ||||
| -rwxr-xr-x | scripts/check_extable.sh | 146 | ||||
| -rw-r--r-- | scripts/mod/modpost.c | 341 |
4 files changed, 440 insertions, 60 deletions
diff --git a/kernel/module.c b/kernel/module.c index 650b038..42a1d2a 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -387,9 +387,9 @@ static bool check_symbol(const struct symsearch *syms, pr_warn("Symbol %s is marked as UNUSED, however this module is " "using it.\n", fsa->name); pr_warn("This symbol will go away in the future.\n"); - pr_warn("Please evalute if this is the right api to use and if " - "it really is, submit a report the linux kernel " - "mailinglist together with submitting your code for " + pr_warn("Please evaluate if this is the right api to use and " + "if it really is, submit a report to the linux kernel " + "mailing list together with submitting your code for " "inclusion.\n"); } #endif @@ -2511,7 +2511,8 @@ static int copy_module_from_user(const void __user *umod, unsigned long len, return err; /* Suck in entire file: we'll want most of it. */ - info->hdr = vmalloc(info->len); + info->hdr = __vmalloc(info->len, + GFP_KERNEL | __GFP_HIGHMEM | __GFP_NOWARN, PAGE_KERNEL); if (!info->hdr) return -ENOMEM; diff --git a/kernel/params.c b/kernel/params.c index 728e05b..a22d6a7 100644 --- a/kernel/params.c +++ b/kernel/params.c @@ -173,9 +173,9 @@ static char *next_arg(char *args, char **param, char **val) if (args[i-1] == '"') args[i-1] = '\0'; } - if (quoted && args[i-1] == '"') - args[i-1] = '\0'; } + if (quoted && args[i-1] == '"') + args[i-1] = '\0'; if (args[i]) { args[i] = '\0'; diff --git a/scripts/check_extable.sh b/scripts/check_extable.sh new file mode 100755 index 0000000..0fb6b1c --- /dev/null +++ b/scripts/check_extable.sh @@ -0,0 +1,146 @@ +#! /bin/bash +# (c) 2015, Quentin Casasnovas <quentin.casasnovas@oracle.com> + +obj=$1 + +file ${obj} | grep -q ELF || (echo "${obj} is not and ELF file." 1>&2 ; exit 0) + +# Bail out early if there isn't an __ex_table section in this object file. +objdump -hj __ex_table ${obj} 2> /dev/null > /dev/null +[ $? -ne 0 ] && exit 0 + +white_list=.text,.fixup + +suspicious_relocs=$(objdump -rj __ex_table ${obj} | tail -n +6 | + grep -v $(eval echo -e{${white_list}}) | awk '{print $3}') + +# No suspicious relocs in __ex_table, jobs a good'un +[ -z "${suspicious_relocs}" ] && exit 0 + + +# After this point, something is seriously wrong since we just found out we +# have some relocations in __ex_table which point to sections which aren't +# white listed. If you're adding a new section in the Linux kernel, and +# you're expecting this section to contain code which can fault (i.e. the +# __ex_table relocation to your new section is expected), simply add your +# new section to the white_list variable above. If not, you're probably +# doing something wrong and the rest of this code is just trying to print +# you more information about it. + +function find_section_offset_from_symbol() +{ + eval $(objdump -t ${obj} | grep ${1} | sed 's/\([0-9a-f]\+\) .\{7\} \([^ \t]\+\).*/section="\2"; section_offset="0x\1" /') + + # addr2line takes addresses in hexadecimal... + section_offset=$(printf "0x%016x" $(( ${section_offset} + $2 )) ) +} + +function find_symbol_and_offset_from_reloc() +{ + # Extract symbol and offset from the objdump output + eval $(echo $reloc | sed 's/\([^+]\+\)+\?\(0x[0-9a-f]\+\)\?/symbol="\1"; symbol_offset="\2"/') + + # When the relocation points to the begining of a symbol or section, it + # won't print the offset since it is zero. + if [ -z "${symbol_offset}" ]; then + symbol_offset=0x0 + fi +} + +function find_alt_replacement_target() +{ + # The target of the .altinstr_replacement is the relocation just before + # the .altinstr_replacement one. + eval $(objdump -rj .altinstructions ${obj} | grep -B1 "${section}+${section_offset}" | head -n1 | awk '{print $3}' | + sed 's/\([^+]\+\)+\(0x[0-9a-f]\+\)/alt_target_section="\1"; alt_target_offset="\2"/') +} + +function handle_alt_replacement_reloc() +{ + # This will define alt_target_section and alt_target_section_offset + find_alt_replacement_target ${section} ${section_offset} + + echo "Error: found a reference to .altinstr_replacement in __ex_table:" + addr2line -fip -j ${alt_target_section} -e ${obj} ${alt_target_offset} | awk '{print "\t" $0}' + + error=true +} + +function is_executable_section() +{ + objdump -hwj ${section} ${obj} | grep -q CODE + return $? +} + +function handle_suspicious_generic_reloc() +{ + if is_executable_section ${section}; then + # We've got a relocation to a non white listed _executable_ + # section, print a warning so the developper adds the section to + # the white list or fix his code. We try to pretty-print the file + # and line number where that relocation was added. + echo "Warning: found a reference to section \"${section}\" in __ex_table:" + addr2line -fip -j ${section} -e ${obj} ${section_offset} | awk '{print "\t" $0}' + else + # Something is definitively wrong here since we've got a relocation + # to a non-executable section, there's no way this would ever be + # running in the kernel. + echo "Error: found a reference to non-executable section \"${section}\" in __ex_table at offset ${section_offset}" + error=true + fi +} + +function handle_suspicious_reloc() +{ + case "${section}" in + ".altinstr_replacement") + handle_alt_replacement_reloc ${section} ${section_offset} + ;; + *) + handle_suspicious_generic_reloc ${section} ${section_offset} + ;; + esac +} + +function diagnose() +{ + + for reloc in ${suspicious_relocs}; do + # Let's find out where the target of the relocation in __ex_table + # is, this will define ${symbol} and ${symbol_offset} + find_symbol_and_offset_from_reloc ${reloc} + + # When there's a global symbol at the place of the relocation, + # objdump will use it instead of giving us a section+offset, so + # let's find out which section is this symbol in and the total + # offset withing that section. + find_section_offset_from_symbol ${symbol} ${symbol_offset} + + # In this case objdump was presenting us with a reloc to a symbol + # rather than a section. Now that we've got the actual section, + # we can skip it if it's in the white_list. + if [ -z "$( echo $section | grep -v $(eval echo -e{${white_list}}))" ]; then + continue; + fi + + # Will either print a warning if the relocation happens to be in a + # section we do not know but has executable bit set, or error out. + handle_suspicious_reloc + done +} + +function check_debug_info() { + objdump -hj .debug_info ${obj} 2> /dev/null > /dev/null || + echo -e "${obj} does not contain debug information, the addr2line output will be limited.\n" \ + "Recompile ${obj} with CONFIG_DEBUG_INFO to get a more useful output." +} + +check_debug_info + +diagnose + +if [ "${error}" ]; then + exit 1 +fi + +exit 0 diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index d439856..91ee1b2 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -776,6 +776,7 @@ static const char *sech_name(struct elf_info *elf, Elf_Shdr *sechdr) * "foo" will match an exact string equal to "foo" * "*foo" will match a string that ends with "foo" * "foo*" will match a string that begins with "foo" + * "*foo*" will match a string that contains "foo" */ static int match(const char *sym, const char * const pat[]) { @@ -784,8 +785,17 @@ static int match(const char *sym, const char * const pat[]) p = *pat++; const char *endp = p + strlen(p) - 1; + /* "*foo*" */ + if (*p == '*' && *endp == '*') { + char *here, *bare = strndup(p + 1, strlen(p) - 2); + + here = strstr(sym, bare); + free(bare); + if (here != NULL) + return 1; + } /* "*foo" */ - if (*p == '*') { + else if (*p == '*') { if (strrcmp(sym, p + 1) == 0) return 1; } @@ -873,7 +883,10 @@ static void check_section(const char *modname, struct elf_info *elf, #define ALL_EXIT_SECTIONS EXIT_SECTIONS, ALL_XXXEXIT_SECTIONS #define DATA_SECTIONS ".data", ".data.rel" -#define TEXT_SECTIONS ".text", ".text.unlikely" +#define TEXT_SECTIONS ".text", ".text.unlikely", ".sched.text", \ + ".kprobes.text" +#define OTHER_TEXT_SECTIONS ".ref.text", ".head.text", ".spinlock.text", \ + ".fixup", ".entry.text", ".exception.text", ".text.*" #define INIT_SECTIONS ".init.*" #define MEM_INIT_SECTIONS ".meminit.*" @@ -881,6 +894,9 @@ static void check_section(const char *modname, struct elf_info *elf, #define EXIT_SECTIONS ".exit.*" #define MEM_EXIT_SECTIONS ".memexit.*" +#define ALL_TEXT_SECTIONS ALL_INIT_TEXT_SECTIONS, ALL_EXIT_TEXT_SECTIONS, \ + TEXT_SECTIONS, OTHER_TEXT_SECTIONS + /* init data sections */ static const char *const init_data_sections[] = { ALL_INIT_DATA_SECTIONS, NULL }; @@ -892,6 +908,9 @@ static const char *const init_sections[] = { ALL_INIT_SECTIONS, NULL }; static const char *const init_exit_sections[] = {ALL_INIT_SECTIONS, ALL_EXIT_SECTIONS, NULL }; +/* all text sections */ +static const char *const text_sections[] = { ALL_TEXT_SECTIONS, NULL }; + /* data section */ static const char *const data_sections[] = { DATA_SECTIONS, NULL }; @@ -910,6 +929,7 @@ static const char *const data_sections[] = { DATA_SECTIONS, NULL }; static const char *const head_sections[] = { ".head.text*", NULL }; static const char *const linker_symbols[] = { "__init_begin", "_sinittext", "_einittext", NULL }; +static const char *const optim_symbols[] = { "*.constprop.*", NULL }; enum mismatch { TEXT_TO_ANY_INIT, @@ -921,34 +941,65 @@ enum mismatch { ANY_INIT_TO_ANY_EXIT, ANY_EXIT_TO_ANY_INIT, EXPORT_TO_INIT_EXIT, + EXTABLE_TO_NON_TEXT, }; +/** + * Describe how to match sections on different criterias: + * + * @fromsec: Array of sections to be matched. + * + * @bad_tosec: Relocations applied to a section in @fromsec to a section in + * this array is forbidden (black-list). Can be empty. + * + * @good_tosec: Relocations applied to a section in @fromsec must be + * targetting sections in this array (white-list). Can be empty. + * + * @mismatch: Type of mismatch. + * + * @symbol_white_list: Do not match a relocation to a symbol in this list + * even if it is targetting a section in @bad_to_sec. + * + * @handler: Specific handler to call when a match is found. If NULL, + * default_mismatch_handler() will be called. + * + */ struct sectioncheck { const char *fromsec[20]; - const char *tosec[20]; + const char *bad_tosec[20]; + const char *good_tosec[20]; enum mismatch mismatch; const char *symbol_white_list[20]; + void (*handler)(const char *modname, struct elf_info *elf, + const struct sectioncheck* const mismatch, + Elf_Rela *r, Elf_Sym *sym, const char *fromsec); + }; +static void extable_mismatch_handler(const char *modname, struct elf_info *elf, + const struct sectioncheck* const mismatch, + Elf_Rela *r, Elf_Sym *sym, + const char *fromsec); + static const struct sectioncheck sectioncheck[] = { /* Do not reference init/exit code/data from * normal code and data */ { .fromsec = { TEXT_SECTIONS, NULL }, - .tosec = { ALL_INIT_SECTIONS, NULL }, + .bad_tosec = { ALL_INIT_SECTIONS, NULL }, .mismatch = TEXT_TO_ANY_INIT, .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, }, { .fromsec = { DATA_SECTIONS, NULL }, - .tosec = { ALL_XXXINIT_SECTIONS, NULL }, + .bad_tosec = { ALL_XXXINIT_SECTIONS, NULL }, .mismatch = DATA_TO_ANY_INIT, .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, }, { .fromsec = { DATA_SECTIONS, NULL }, - .tosec = { INIT_SECTIONS, NULL }, + .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = DATA_TO_ANY_INIT, .symbol_white_list = { "*_template", "*_timer", "*_sht", "*_ops", @@ -957,56 +1008,66 @@ static const struct sectioncheck sectioncheck[] = { }, { .fromsec = { TEXT_SECTIONS, NULL }, - .tosec = { ALL_EXIT_SECTIONS, NULL }, + .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, .mismatch = TEXT_TO_ANY_EXIT, .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, }, { .fromsec = { DATA_SECTIONS, NULL }, - .tosec = { ALL_EXIT_SECTIONS, NULL }, + .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, .mismatch = DATA_TO_ANY_EXIT, .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, }, /* Do not reference init code/data from meminit code/data */ { .fromsec = { ALL_XXXINIT_SECTIONS, NULL }, - .tosec = { INIT_SECTIONS, NULL }, + .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = XXXINIT_TO_SOME_INIT, .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, }, /* Do not reference exit code/data from memexit code/data */ { .fromsec = { ALL_XXXEXIT_SECTIONS, NULL }, - .tosec = { EXIT_SECTIONS, NULL }, + .bad_tosec = { EXIT_SECTIONS, NULL }, .mismatch = XXXEXIT_TO_SOME_EXIT, .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, }, /* Do not use exit code/data from init code */ { .fromsec = { ALL_INIT_SECTIONS, NULL }, - .tosec = { ALL_EXIT_SECTIONS, NULL }, + .bad_tosec = { ALL_EXIT_SECTIONS, NULL }, .mismatch = ANY_INIT_TO_ANY_EXIT, .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, }, /* Do not use init code/data from exit code */ { .fromsec = { ALL_EXIT_SECTIONS, NULL }, - .tosec = { ALL_INIT_SECTIONS, NULL }, + .bad_tosec = { ALL_INIT_SECTIONS, NULL }, .mismatch = ANY_EXIT_TO_ANY_INIT, .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, }, { .fromsec = { ALL_PCI_INIT_SECTIONS, NULL }, - .tosec = { INIT_SECTIONS, NULL }, + .bad_tosec = { INIT_SECTIONS, NULL }, .mismatch = ANY_INIT_TO_ANY_EXIT, .symbol_white_list = { NULL }, }, /* Do not export init/exit functions or data */ { .fromsec = { "__ksymtab*", NULL }, - .tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, + .bad_tosec = { INIT_SECTIONS, EXIT_SECTIONS, NULL }, .mismatch = EXPORT_TO_INIT_EXIT, .symbol_white_list = { DEFAULT_SYMBOL_WHITE_LIST, NULL }, +}, +{ + .fromsec = { "__ex_table", NULL }, + /* If you're adding any new black-listed sections in here, consider + * adding a special 'printer' for them in scripts/check_extable. + */ + .bad_tosec = { ".altinstr_replacement", NULL }, + .good_tosec = {ALL_TEXT_SECTIONS , NULL}, + .mismatch = EXTABLE_TO_NON_TEXT, + .handler = extable_mismatch_handler, } }; @@ -1017,10 +1078,22 @@ static const struct sectioncheck *section_mismatch( int elems = sizeof(sectioncheck) / sizeof(struct sectioncheck); const struct sectioncheck *check = §ioncheck[0]; + /* + * The target section could be the SHT_NUL section when we're + * handling relocations to un-resolved symbols, trying to match it + * doesn't make much sense and causes build failures on parisc and + * mn10300 architectures. + */ + if (*tosec == '\0') + return NULL; + for (i = 0; i < elems; i++) { - if (match(fromsec, check->fromsec) && - match(tosec, check->tosec)) - return check; + if (match(fromsec, check->fromsec)) { + if (check->bad_tosec[0] && match(tosec, check->bad_tosec)) + return check; + if (check->good_tosec[0] && !match(tosec, check->good_tosec)) + return check; + } check++; } return NULL; @@ -1067,6 +1140,17 @@ static const struct sectioncheck *section_mismatch( * This pattern is identified by * refsymname = __init_begin, _sinittext, _einittext * + * Pattern 5: + * GCC may optimize static inlines when fed constant arg(s) resulting + * in functions like cpumask_empty() -- generating an associated symbol + * cpumask_empty.constprop.3 that appears in the audit. If the const that + * is passed in comes from __init, like say nmi_ipi_mask, we get a + * meaningless section warning. May need to add isra symbols too... + * This pattern is identified by + * tosec = init section + * fromsec = text section + * refsymname = *.constprop.* + * **/ static int secref_whitelist(const struct sectioncheck *mismatch, const char *fromsec, const char *fromsym, @@ -1099,6 +1183,12 @@ static int secref_whitelist(const struct sectioncheck *mismatch, if (match(tosym, linker_symbols)) return 0; + /* Check for pattern 5 */ + if (match(fromsec, text_sections) && + match(tosec, init_sections) && + match(fromsym, optim_symbols)) + return 0; + return 1; } @@ -1261,6 +1351,15 @@ static void print_section_list(const char * const list[20]) fprintf(stderr, "\n"); } +static inline void get_pretty_name(int is_func, const char** name, const char** name_p) +{ + switch (is_func) { + case 0: *name = "variable"; *name_p = ""; break; + case 1: *name = "function"; *name_p = "()"; break; + default: *name = "(unknown reference)"; *name_p = ""; break; + } +} + /* * Print a warning about a section mismatch. * Try to find symbols near it so user can find it. @@ -1280,21 +1379,13 @@ static void report_sec_mismatch(const char *modname, char *prl_from; char *prl_to; - switch (from_is_func) { - case 0: from = "variable"; from_p = ""; break; - case 1: from = "function"; from_p = "()"; break; - default: from = "(unknown reference)"; from_p = ""; break; - } - switch (to_is_func) { - case 0: to = "variable"; to_p = ""; break; - case 1: to = "function"; to_p = "()"; break; - default: to = "(unknown reference)"; to_p = ""; break; - } - sec_mismatch_count++; if (!sec_mismatch_verbose) return; + get_pretty_name(from_is_func, &from, &from_p); + get_pretty_name(to_is_func, &to, &to_p); + warn("%s(%s+0x%llx): Section mismatch in reference from the %s %s%s " "to the %s %s:%s%s\n", modname, fromsec, fromaddr, from, fromsym, from_p, to, tosec, @@ -1408,41 +1499,179 @@ static void report_sec_mismatch(const char *modname, tosym, prl_to, prl_to, tosym); free(prl_to); break; + case EXTABLE_TO_NON_TEXT: + fatal("There's a special handler for this mismatch type, " + "we should never get here."); + break; } fprintf(stderr, "\n"); } -static void check_section_mismatch(const char *modname, struct elf_info *elf, - Elf_Rela *r, Elf_Sym *sym, const char *fromsec) +static void default_mismatch_handler(const char *modname, struct elf_info *elf, + const struct sectioncheck* const mismatch, + Elf_Rela *r, Elf_Sym *sym, const char *fromsec) { const char *tosec; - const struct sectioncheck *mismatch; + Elf_Sym *to; + Elf_Sym *from; + const char *tosym; + const char *fromsym; + + from = find_elf_symbol2(elf, r->r_offset, fromsec); + fromsym = sym_name(elf, from); + + if (!strncmp(fromsym, "reference___initcall", + sizeof("reference___initcall")-1)) + return; tosec = sec_name(elf, get_secindex(elf, sym)); - mismatch = section_mismatch(fromsec, tosec); + to = find_elf_symbol(elf, r->r_addend, sym); + tosym = sym_name(elf, to); + + /* check whitelist - we may ignore it */ + if (secref_whitelist(mismatch, + fromsec, fromsym, tosec, tosym)) { + report_sec_mismatch(modname, mismatch, + fromsec, r->r_offset, fromsym, + is_function(from), tosec, tosym, + is_function(to)); + } +} + +static int is_executable_section(struct elf_info* elf, unsigned int section_index) +{ + if (section_index > elf->num_sections) + fatal("section_index is outside elf->num_sections!\n"); + + return ((elf->sechdrs[section_index].sh_flags & SHF_EXECINSTR) == SHF_EXECINSTR); +} + +/* + * We rely on a gross hack in section_rel[a]() calling find_extable_entry_size() + * to know the sizeof(struct exception_table_entry) for the target architecture. + */ +static unsigned int extable_entry_size = 0; +static void find_extable_entry_size(const char* const sec, const Elf_Rela* r) +{ + /* + * If we're currently checking the second relocation within __ex_table, + * that relocation offset tells us the offsetof(struct + * exception_table_entry, fixup) which is equal to sizeof(struct + * exception_table_entry) divided by two. We use that to our advantage + * since there's no portable way to get that size as every architecture + * seems to go with different sized types. Not pretty but better than + * hard-coding the size for every architecture.. + */ + if (!extable_entry_size) + extable_entry_size = r->r_offset * 2; +} + +static inline bool is_extable_fault_address(Elf_Rela *r) +{ + /* + * extable_entry_size is only discovered after we've handled the + * _second_ relocation in __ex_table, so only abort when we're not + * handling the first reloc and extable_entry_size is zero. + */ + if (r->r_offset && extable_entry_size == 0) + fatal("extable_entry size hasn't been discovered!\n"); + + return ((r->r_offset == 0) || + (r->r_offset % extable_entry_size == 0)); +} + +#define is_second_extable_reloc(Start, Cur, Sec) \ + (((Cur) == (Start) + 1) && (strcmp("__ex_table", (Sec)) == 0)) + +static void report_extable_warnings(const char* modname, struct elf_info* elf, + const struct sectioncheck* const mismatch, + Elf_Rela* r, Elf_Sym* sym, + const char* fromsec, const char* tosec) +{ + Elf_Sym* fromsym = find_elf_symbol2(elf, r->r_offset, fromsec); + const char* fromsym_name = sym_name(elf, fromsym); + Elf_Sym* tosym = find_elf_symbol(elf, r->r_addend, sym); + const char* tosym_name = sym_name(elf, tosym); + const char* from_pretty_name; + const char* from_pretty_name_p; + const char* to_pretty_name; + const char* to_pretty_name_p; + + get_pretty_name(is_function(fromsym), + &from_pretty_name, &from_pretty_name_p); + get_pretty_name(is_function(tosym), + &to_pretty_name, &to_pretty_name_p); + + warn("%s(%s+0x%lx): Section mismatch in reference" + " from the %s %s%s to the %s %s:%s%s\n", + modname, fromsec, (long)r->r_offset, from_pretty_name, + fromsym_name, from_pretty_name_p, + to_pretty_name, tosec, tosym_name, to_pretty_name_p); + + if (!match(tosec, mismatch->bad_tosec) && + is_executable_section(elf, get_secindex(elf, sym))) + fprintf(stderr, + "The relocation at %s+0x%lx references\n" + "section \"%s\" which is not in the list of\n" + "authorized sections. If you're adding a new section\n" + "and/or if this reference is valid, add \"%s\" to the\n" + "list of authorized sections to jump to on fault.\n" + "This can be achieved by adding \"%s\" to \n" + "OTHER_TEXT_SECTIONS in scripts/mod/modpost.c.\n", + fromsec, (long)r->r_offset, tosec, tosec, tosec); +} + +static void extable_mismatch_handler(const char* modname, struct elf_info *elf, + const struct sectioncheck* const mismatch, + Elf_Rela* r, Elf_Sym* sym, + const char *fromsec) +{ + const char* tosec = sec_name(elf, get_secindex(elf, sym)); + + sec_mismatch_count++; + + if (sec_mismatch_verbose) + report_extable_warnings(modname, elf, mismatch, r, sym, + fromsec, tosec); + + if (match(tosec, mismatch->bad_tosec)) + fatal("The relocation at %s+0x%lx references\n" + "section \"%s\" which is black-listed.\n" + "Something is seriously wrong and should be fixed.\n" + "You might get more information about where this is\n" + "coming from by using scripts/check_extable.sh %s\n", + fromsec, (long)r->r_offset, tosec, modname); + else if (!is_executable_section(elf, get_secindex(elf, sym))) { + if (is_extable_fault_address(r)) + fatal("The relocation at %s+0x%lx references\n" + "section \"%s\" which is not executable, IOW\n" + "it is not possible for the kernel to fault\n" + "at that address. Something is seriously wrong\n" + "and should be fixed.\n", + fromsec, (long)r->r_offset, tosec); + else + fatal("The relocation at %s+0x%lx references\n" + "section \"%s\" which is not executable, IOW\n" + "the kernel will fault if it ever tries to\n" + "jump to it. Something is seriously wrong\n" + "and should be fixed.\n", + fromsec, (long)r->r_offset, tosec); + } +} + +static void check_section_mismatch(const char *modname, struct elf_info *elf, + Elf_Rela *r, Elf_Sym *sym, const char *fromsec) +{ + const char *tosec = sec_name(elf, get_secindex(elf, sym));; + const struct sectioncheck *mismatch = section_mismatch(fromsec, tosec); + if (mismatch) { - Elf_Sym *to; - Elf_Sym *from; - const char *tosym; - const char *fromsym; - - from = find_elf_symbol2(elf, r->r_offset, fromsec); - fromsym = sym_name(elf, from); - to = find_elf_symbol(elf, r->r_addend, sym); - tosym = sym_name(elf, to); - - if (!strncmp(fromsym, "reference___initcall", - sizeof("reference___initcall")-1)) - return; - - /* check whitelist - we may ignore it */ - if (secref_whitelist(mismatch, - fromsec, fromsym, tosec, tosym)) { - report_sec_mismatch(modname, mismatch, - fromsec, r->r_offset, fromsym, - is_function(from), tosec, tosym, - is_function(to)); - } + if (mismatch->handler) + mismatch->handler(modname, elf, mismatch, + r, sym, fromsec); + else + default_mismatch_handler(modname, elf, mismatch, + r, sym, fromsec); } } @@ -1582,6 +1811,8 @@ static void section_rela(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; + if (is_second_extable_reloc(start, rela, fromsec)) + find_extable_entry_size(fromsec, &r); check_section_mismatch(modname, elf, &r, sym, fromsec); } } @@ -1640,6 +1871,8 @@ static void section_rel(const char *modname, struct elf_info *elf, /* Skip special sections */ if (is_shndx_special(sym->st_shndx)) continue; + if (is_second_extable_reloc(start, rel, fromsec)) + find_extable_entry_size(fromsec, &r); check_section_mismatch(modname, elf, &r, sym, fromsec); } } |
