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| author | Peter Maydell <peter.maydell@linaro.org> | 2017-02-04 23:05:33 +0000 |
|---|---|---|
| committer | Laurent Vivier <laurent@vivier.eu> | 2017-02-16 15:29:30 +0100 |
| commit | 1e06262da615fcc0ddd658f96c5673a73b856fb6 (patch) | |
| tree | fa9b132e6642534c046b7e9bc0e98f3156a184a6 /linux-user | |
| parent | 26920a2961f7cc86bfbdb2184c0ec261d5629c2f (diff) | |
| download | qemu-1e06262da615fcc0ddd658f96c5673a73b856fb6.tar.gz | |
linux-user: Use correct types in load_symbols()
Coverity doesn't like the code in load_symbols() which assumes
it can use 'int' for a variable that might hold an offset into
the guest ELF file, because in a 64-bit guest that could
overflow. Guest binaries with 2GB sections aren't very likely
and this isn't a security issue because we fully trust the
guest linux-user binary anyway, but we might as well use the
right types, which will placate Coverity. Use uint64_t to
hold section sizes, and bail out if the symbol table is too
large rather than just overflowing an int.
(Coverity issue CID1005776)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <1486249533-5260-1-git-send-email-peter.maydell@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Diffstat (limited to 'linux-user')
| -rw-r--r-- | linux-user/elfload.c | 22 |
1 files changed, 15 insertions, 7 deletions
diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 8271227339..f520d7723c 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -2262,6 +2262,7 @@ static int symcmp(const void *s0, const void *s1) static void load_symbols(struct elfhdr *hdr, int fd, abi_ulong load_bias) { int i, shnum, nsyms, sym_idx = 0, str_idx = 0; + uint64_t segsz; struct elf_shdr *shdr; char *strings = NULL; struct syminfo *s = NULL; @@ -2293,19 +2294,26 @@ static void load_symbols(struct elfhdr *hdr, int fd, abi_ulong load_bias) goto give_up; } - i = shdr[str_idx].sh_size; - s->disas_strtab = strings = g_try_malloc(i); - if (!strings || pread(fd, strings, i, shdr[str_idx].sh_offset) != i) { + segsz = shdr[str_idx].sh_size; + s->disas_strtab = strings = g_try_malloc(segsz); + if (!strings || + pread(fd, strings, segsz, shdr[str_idx].sh_offset) != segsz) { goto give_up; } - i = shdr[sym_idx].sh_size; - syms = g_try_malloc(i); - if (!syms || pread(fd, syms, i, shdr[sym_idx].sh_offset) != i) { + segsz = shdr[sym_idx].sh_size; + syms = g_try_malloc(segsz); + if (!syms || pread(fd, syms, segsz, shdr[sym_idx].sh_offset) != segsz) { goto give_up; } - nsyms = i / sizeof(struct elf_sym); + if (segsz / sizeof(struct elf_sym) > INT_MAX) { + /* Implausibly large symbol table: give up rather than ploughing + * on with the number of symbols calculation overflowing + */ + goto give_up; + } + nsyms = segsz / sizeof(struct elf_sym); for (i = 0; i < nsyms; ) { bswap_sym(syms + i); /* Throw away entries which we do not need. */ |