diff options
Diffstat (limited to 'contrib/file/src/readelf.c')
| -rw-r--r-- | contrib/file/src/readelf.c | 219 |
1 files changed, 199 insertions, 20 deletions
diff --git a/contrib/file/src/readelf.c b/contrib/file/src/readelf.c index 2a7fc01..39598f7 100644 --- a/contrib/file/src/readelf.c +++ b/contrib/file/src/readelf.c @@ -27,7 +27,7 @@ #include "file.h" #ifndef lint -FILE_RCSID("@(#)$File: readelf.c,v 1.122 2015/09/10 13:59:32 christos Exp $") +FILE_RCSID("@(#)$File: readelf.c,v 1.127 2015/11/18 12:29:29 christos Exp $") #endif #ifdef BUILTIN_ELF @@ -50,7 +50,7 @@ private int dophn_exec(struct magic_set *, int, int, int, off_t, int, size_t, private int doshn(struct magic_set *, int, int, int, off_t, int, size_t, off_t, int, int, int *, uint16_t *); private size_t donote(struct magic_set *, void *, size_t, size_t, int, - int, size_t, int *, uint16_t *); + int, size_t, int *, uint16_t *, int, off_t, int, off_t); #define ELF_ALIGN(a) ((((a) + align - 1) / align) * align) @@ -177,6 +177,11 @@ getu64(int swap, uint64_t value) elf_getu32(swap, ph32.p_align) : 4) \ : (off_t) (ph64.p_align ? \ elf_getu64(swap, ph64.p_align) : 4))) +#define xph_vaddr (size_t)((clazz == ELFCLASS32 \ + ? (off_t) (ph32.p_vaddr ? \ + elf_getu32(swap, ph32.p_vaddr) : 4) \ + : (off_t) (ph64.p_vaddr ? \ + elf_getu64(swap, ph64.p_vaddr) : 4))) #define xph_filesz (size_t)((clazz == ELFCLASS32 \ ? elf_getu32(swap, ph32.p_filesz) \ : elf_getu64(swap, ph64.p_filesz))) @@ -187,8 +192,8 @@ getu64(int swap, uint64_t value) ? elf_getu32(swap, ph32.p_memsz) \ : elf_getu64(swap, ph64.p_memsz))) #define xnh_sizeof (clazz == ELFCLASS32 \ - ? sizeof nh32 \ - : sizeof nh64) + ? sizeof(nh32) \ + : sizeof(nh64)) #define xnh_type (clazz == ELFCLASS32 \ ? elf_getu32(swap, nh32.n_type) \ : elf_getu32(swap, nh64.n_type)) @@ -213,6 +218,18 @@ getu64(int swap, uint64_t value) #define xcap_val (clazz == ELFCLASS32 \ ? elf_getu32(swap, cap32.c_un.c_val) \ : elf_getu64(swap, cap64.c_un.c_val)) +#define xauxv_addr (clazz == ELFCLASS32 \ + ? (void *)&auxv32 \ + : (void *)&auxv64) +#define xauxv_sizeof (clazz == ELFCLASS32 \ + ? sizeof(auxv32) \ + : sizeof(auxv64)) +#define xauxv_type (clazz == ELFCLASS32 \ + ? elf_getu32(swap, auxv32.a_type) \ + : elf_getu64(swap, auxv64.a_type)) +#define xauxv_val (clazz == ELFCLASS32 \ + ? elf_getu32(swap, auxv32.a_v) \ + : elf_getu64(swap, auxv64.a_v)) #ifdef ELFCORE /* @@ -302,6 +319,7 @@ private const char os_style_names[][8] = { #define FLAGS_DID_NETBSD_CMODEL 0x040 #define FLAGS_DID_NETBSD_UNKNOWN 0x080 #define FLAGS_IS_CORE 0x100 +#define FLAGS_DID_AUXV 0x200 private int dophn_core(struct magic_set *ms, int clazz, int swap, int fd, off_t off, @@ -312,6 +330,8 @@ dophn_core(struct magic_set *ms, int clazz, int swap, int fd, off_t off, size_t offset, len; unsigned char nbuf[BUFSIZ]; ssize_t bufsize; + off_t ph_off = off; + int ph_num = num; if (size != xph_sizeof) { if (file_printf(ms, ", corrupted program header size") == -1) @@ -351,7 +371,8 @@ dophn_core(struct magic_set *ms, int clazz, int swap, int fd, off_t off, if (offset >= (size_t)bufsize) break; offset = donote(ms, nbuf, offset, (size_t)bufsize, - clazz, swap, 4, flags, notecount); + clazz, swap, 4, flags, notecount, fd, ph_off, + ph_num, fsize); if (offset == 0) break; @@ -813,9 +834,157 @@ do_core_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type, return 0; } +private off_t +get_offset_from_virtaddr(struct magic_set *ms, int swap, int clazz, int fd, + off_t off, int num, off_t fsize, uint64_t virtaddr) +{ + Elf32_Phdr ph32; + Elf64_Phdr ph64; + + /* + * Loop through all the program headers and find the header with + * virtual address in which the "virtaddr" belongs to. + */ + for ( ; num; num--) { + if (pread(fd, xph_addr, xph_sizeof, off) < (ssize_t)xph_sizeof) { + file_badread(ms); + return -1; + } + off += xph_sizeof; + + if (fsize != SIZE_UNKNOWN && xph_offset > fsize) { + /* Perhaps warn here */ + continue; + } + + if (virtaddr >= xph_vaddr && virtaddr < xph_vaddr + xph_filesz) + return xph_offset + (virtaddr - xph_vaddr); + } + return 0; +} + +private size_t +get_string_on_virtaddr(struct magic_set *ms, + int swap, int clazz, int fd, off_t ph_off, int ph_num, + off_t fsize, uint64_t virtaddr, char *buf, ssize_t buflen) +{ + char *bptr; + off_t offset; + + if (buflen == 0) + return 0; + + offset = get_offset_from_virtaddr(ms, swap, clazz, fd, ph_off, ph_num, + fsize, virtaddr); + if ((buflen = pread(fd, buf, buflen, offset)) <= 0) { + file_badread(ms); + return 0; + } + + buf[buflen - 1] = '\0'; + + /* We expect only printable characters, so return if buffer contains + * non-printable character before the '\0' or just '\0'. */ + for (bptr = buf; *bptr && isprint((unsigned char)*bptr); bptr++) + continue; + if (*bptr != '\0') + return 0; + + return bptr - buf; +} + + +private int +do_auxv_note(struct magic_set *ms, unsigned char *nbuf, uint32_t type, + int swap, uint32_t namesz __attribute__((__unused__)), + uint32_t descsz __attribute__((__unused__)), + size_t noff __attribute__((__unused__)), size_t doff, + int *flags, size_t size __attribute__((__unused__)), int clazz, + int fd, off_t ph_off, int ph_num, off_t fsize) +{ +#ifdef ELFCORE + Aux32Info auxv32; + Aux64Info auxv64; + size_t elsize = xauxv_sizeof; + const char *tag; + int is_string; + size_t nval; + + if (type != NT_AUXV || (*flags & FLAGS_IS_CORE) == 0) + return 0; + + *flags |= FLAGS_DID_AUXV; + + nval = 0; + for (size_t off = 0; off + elsize <= descsz; off += elsize) { + (void)memcpy(xauxv_addr, &nbuf[doff + off], xauxv_sizeof); + /* Limit processing to 50 vector entries to prevent DoS */ + if (nval++ >= 50) { + file_error(ms, 0, "Too many ELF Auxv elements"); + return 1; + } + + switch(xauxv_type) { + case AT_LINUX_EXECFN: + is_string = 1; + tag = "execfn"; + break; + case AT_LINUX_PLATFORM: + is_string = 1; + tag = "platform"; + break; + case AT_LINUX_UID: + is_string = 0; + tag = "real uid"; + break; + case AT_LINUX_GID: + is_string = 0; + tag = "real gid"; + break; + case AT_LINUX_EUID: + is_string = 0; + tag = "effective uid"; + break; + case AT_LINUX_EGID: + is_string = 0; + tag = "effective gid"; + break; + default: + is_string = 0; + tag = NULL; + break; + } + + if (tag == NULL) + continue; + + if (is_string) { + char buf[256]; + ssize_t buflen; + buflen = get_string_on_virtaddr(ms, swap, clazz, fd, + ph_off, ph_num, fsize, xauxv_val, buf, sizeof(buf)); + + if (buflen == 0) + continue; + + if (file_printf(ms, ", %s: '%s'", tag, buf) == -1) + return 0; + } else { + if (file_printf(ms, ", %s: %d", tag, (int) xauxv_val) + == -1) + return 0; + } + } + return 1; +#else + return 0; +#endif +} + private size_t donote(struct magic_set *ms, void *vbuf, size_t offset, size_t size, - int clazz, int swap, size_t align, int *flags, uint16_t *notecount) + int clazz, int swap, size_t align, int *flags, uint16_t *notecount, + int fd, off_t ph_off, int ph_num, off_t fsize) { Elf32_Nhdr nh32; Elf64_Nhdr nh64; @@ -839,6 +1008,7 @@ donote(struct magic_set *ms, void *vbuf, size_t offset, size_t size, namesz = xnh_namesz; descsz = xnh_descsz; + if ((namesz == 0) && (descsz == 0)) { /* * We're out of note headers. @@ -876,28 +1046,36 @@ donote(struct magic_set *ms, void *vbuf, size_t offset, size_t size, return (offset >= size) ? offset : size; } + if ((*flags & FLAGS_DID_OS_NOTE) == 0) { if (do_os_note(ms, nbuf, xnh_type, swap, namesz, descsz, noff, doff, flags)) - return size; + return offset; } if ((*flags & FLAGS_DID_BUILD_ID) == 0) { if (do_bid_note(ms, nbuf, xnh_type, swap, namesz, descsz, noff, doff, flags)) - return size; + return offset; } if ((*flags & FLAGS_DID_NETBSD_PAX) == 0) { if (do_pax_note(ms, nbuf, xnh_type, swap, namesz, descsz, noff, doff, flags)) - return size; + return offset; } if ((*flags & FLAGS_DID_CORE) == 0) { if (do_core_note(ms, nbuf, xnh_type, swap, namesz, descsz, noff, doff, flags, size, clazz)) - return size; + return offset; + } + + if ((*flags & FLAGS_DID_AUXV) == 0) { + if (do_auxv_note(ms, nbuf, xnh_type, swap, + namesz, descsz, noff, doff, flags, size, clazz, + fd, ph_off, ph_num, fsize)) + return offset; } if (namesz == 7 && strcmp((char *)&nbuf[noff], "NetBSD") == 0) { @@ -905,32 +1083,32 @@ donote(struct magic_set *ms, void *vbuf, size_t offset, size_t size, descsz = 100; switch (xnh_type) { case NT_NETBSD_VERSION: - return size; + return offset; case NT_NETBSD_MARCH: if (*flags & FLAGS_DID_NETBSD_MARCH) - return size; + return offset; *flags |= FLAGS_DID_NETBSD_MARCH; if (file_printf(ms, ", compiled for: %.*s", (int)descsz, (const char *)&nbuf[doff]) == -1) - return size; + return offset; break; case NT_NETBSD_CMODEL: if (*flags & FLAGS_DID_NETBSD_CMODEL) - return size; + return offset; *flags |= FLAGS_DID_NETBSD_CMODEL; if (file_printf(ms, ", compiler model: %.*s", (int)descsz, (const char *)&nbuf[doff]) == -1) - return size; + return offset; break; default: if (*flags & FLAGS_DID_NETBSD_UNKNOWN) - return size; + return offset; *flags |= FLAGS_DID_NETBSD_UNKNOWN; if (file_printf(ms, ", note=%u", xnh_type) == -1) - return size; + return offset; break; } - return size; + return offset; } return offset; @@ -1080,7 +1258,8 @@ doshn(struct magic_set *ms, int clazz, int swap, int fd, off_t off, int num, if (noff >= (off_t)xsh_size) break; noff = donote(ms, nbuf, (size_t)noff, - xsh_size, clazz, swap, 4, flags, notecount); + xsh_size, clazz, swap, 4, flags, notecount, + fd, 0, 0, 0); if (noff == 0) break; } @@ -1329,7 +1508,7 @@ dophn_exec(struct magic_set *ms, int clazz, int swap, int fd, off_t off, break; offset = donote(ms, nbuf, offset, (size_t)bufsize, clazz, swap, align, - flags, notecount); + flags, notecount, fd, 0, 0, 0); if (offset == 0) break; } |
