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author | Chen Gang <gang.chen@asianux.com> | 2013-04-15 15:04:43 +0930 |
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committer | Rusty Russell <rusty@rustcorp.com.au> | 2013-04-15 15:17:26 +0930 |
commit | e3f26752f0f8a6aade580115e1e68bcb1a4bc040 (patch) | |
tree | 04e818066d7d0faa64abfe55b4841da984f3812f /kernel/kallsyms.c | |
parent | 07c449bbc6aa514098c4f12c7b04180cec2417c6 (diff) | |
download | op-kernel-dev-e3f26752f0f8a6aade580115e1e68bcb1a4bc040.zip op-kernel-dev-e3f26752f0f8a6aade580115e1e68bcb1a4bc040.tar.gz |
kernel: kallsyms: memory override issue, need check destination buffer length
We don't export any symbols > 128 characters, but if we did then
kallsyms_expand_symbol() would overflow the buffer handed to it.
So we need check destination buffer length when copying.
the related test:
if we define an EXPORT function which name more than 128.
will panic when call kallsyms_lookup_name by init_kprobes on booting.
after check the length (provide this patch), it is ok.
Implementaion:
add additional destination buffer length parameter (maxlen)
if uncompressed string is too long (>= maxlen), it will be truncated.
not check the parameters whether valid, since it is a static function.
Signed-off-by: Chen Gang <gang.chen@asianux.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'kernel/kallsyms.c')
-rw-r--r-- | kernel/kallsyms.c | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 2169fee..3127ad5 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -84,9 +84,11 @@ static int is_ksym_addr(unsigned long addr) /* * Expand a compressed symbol data into the resulting uncompressed string, + * if uncompressed string is too long (>= maxlen), it will be truncated, * given the offset to where the symbol is in the compressed stream. */ -static unsigned int kallsyms_expand_symbol(unsigned int off, char *result) +static unsigned int kallsyms_expand_symbol(unsigned int off, + char *result, size_t maxlen) { int len, skipped_first = 0; const u8 *tptr, *data; @@ -113,15 +115,20 @@ static unsigned int kallsyms_expand_symbol(unsigned int off, char *result) while (*tptr) { if (skipped_first) { + if (maxlen <= 1) + goto tail; *result = *tptr; result++; + maxlen--; } else skipped_first = 1; tptr++; } } - *result = '\0'; +tail: + if (maxlen) + *result = '\0'; /* Return to offset to the next symbol. */ return off; @@ -176,7 +183,7 @@ unsigned long kallsyms_lookup_name(const char *name) unsigned int off; for (i = 0, off = 0; i < kallsyms_num_syms; i++) { - off = kallsyms_expand_symbol(off, namebuf); + off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); if (strcmp(namebuf, name) == 0) return kallsyms_addresses[i]; @@ -195,7 +202,7 @@ int kallsyms_on_each_symbol(int (*fn)(void *, const char *, struct module *, int ret; for (i = 0, off = 0; i < kallsyms_num_syms; i++) { - off = kallsyms_expand_symbol(off, namebuf); + off = kallsyms_expand_symbol(off, namebuf, ARRAY_SIZE(namebuf)); ret = fn(data, namebuf, NULL, kallsyms_addresses[i]); if (ret != 0) return ret; @@ -294,7 +301,8 @@ const char *kallsyms_lookup(unsigned long addr, pos = get_symbol_pos(addr, symbolsize, offset); /* Grab name */ - kallsyms_expand_symbol(get_symbol_offset(pos), namebuf); + kallsyms_expand_symbol(get_symbol_offset(pos), + namebuf, KSYM_NAME_LEN); if (modname) *modname = NULL; return namebuf; @@ -315,7 +323,8 @@ int lookup_symbol_name(unsigned long addr, char *symname) pos = get_symbol_pos(addr, NULL, NULL); /* Grab name */ - kallsyms_expand_symbol(get_symbol_offset(pos), symname); + kallsyms_expand_symbol(get_symbol_offset(pos), + symname, KSYM_NAME_LEN); return 0; } /* See if it's in a module. */ @@ -333,7 +342,8 @@ int lookup_symbol_attrs(unsigned long addr, unsigned long *size, pos = get_symbol_pos(addr, size, offset); /* Grab name */ - kallsyms_expand_symbol(get_symbol_offset(pos), name); + kallsyms_expand_symbol(get_symbol_offset(pos), + name, KSYM_NAME_LEN); modname[0] = '\0'; return 0; } @@ -463,7 +473,7 @@ static unsigned long get_ksymbol_core(struct kallsym_iter *iter) iter->type = kallsyms_get_symbol_type(off); - off = kallsyms_expand_symbol(off, iter->name); + off = kallsyms_expand_symbol(off, iter->name, ARRAY_SIZE(iter->name)); return off - iter->nameoff; } |