diff options
Diffstat (limited to 'libelf/elf_strptr.c')
| -rw-r--r-- | libelf/elf_strptr.c | 30 |
1 files changed, 22 insertions, 8 deletions
diff --git a/libelf/elf_strptr.c b/libelf/elf_strptr.c index ea210459..e72a3a36 100644 --- a/libelf/elf_strptr.c +++ b/libelf/elf_strptr.c @@ -32,6 +32,7 @@ #endif #include <libelf.h> +#include <stdbool.h> #include <stddef.h> #include "libelfP.h" @@ -52,6 +53,22 @@ get_zdata (Elf_Scn *strscn) return zdata; } +static bool validate_str (const char *str, size_t from, size_t to) +{ +#if HAVE_DECL_MEMRCHR + return memrchr (&str[from], '\0', to - from) != NULL; +#else + do { + if (to <= from) + return false; + + to--; + } while (str[to]); + + return true; +#endif +} + char * elf_strptr (Elf *elf, size_t idx, size_t offset) { @@ -166,8 +183,7 @@ elf_strptr (Elf *elf, size_t idx, size_t offset) { /* Make sure the string is NUL terminated. Start from the end, which very likely is a NUL char. */ - if (likely (memrchr (&strscn->zdata_base[offset], - '\0', sh_size - offset) != NULL)) + if (likely (validate_str (strscn->zdata_base, offset, sh_size))) result = &strscn->zdata_base[offset]; else __libelf_seterrno (ELF_E_INVALID_INDEX); @@ -185,8 +201,7 @@ elf_strptr (Elf *elf, size_t idx, size_t offset) /* Make sure the string is NUL terminated. Start from the end, which very likely is a NUL char. */ - if (likely (memrchr (&strscn->rawdata_base[offset], - '\0', sh_size - offset) != NULL)) + if (likely (validate_str (strscn->rawdata_base, offset, sh_size))) result = &strscn->rawdata_base[offset]; else __libelf_seterrno (ELF_E_INVALID_INDEX); @@ -203,10 +218,9 @@ elf_strptr (Elf *elf, size_t idx, size_t offset) { /* Make sure the string is NUL terminated. Start from the end, which very likely is a NUL char. */ - if (likely (memrchr ((char *) dl->data.d.d_buf - + (offset - dl->data.d.d_off), '\0', - (dl->data.d.d_size - - (offset - dl->data.d.d_off))) != NULL)) + if (likely (validate_str ((char *) dl->data.d.d_buf, + offset - dl->data.d.d_off, + dl->data.d.d_size))) result = ((char *) dl->data.d.d_buf + (offset - dl->data.d.d_off)); else |