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>
static void load_symbols(struct elfhdr *hdr, int fd, abi_ulong load_bias)
{
int i, shnum, nsyms, sym_idx = 0, str_idx = 0;
static void load_symbols(struct elfhdr *hdr, int fd, abi_ulong load_bias)
{
int i, shnum, nsyms, sym_idx = 0, str_idx = 0;
struct elf_shdr *shdr;
char *strings = NULL;
struct syminfo *s = NULL;
struct elf_shdr *shdr;
char *strings = NULL;
struct syminfo *s = NULL;
- 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) {
- 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) {
- 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. */
for (i = 0; i < nsyms; ) {
bswap_sym(syms + i);
/* Throw away entries which we do not need. */