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libsanitizer: Hwasan reporting check for dladdr failing

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In `GetGlobalSizeFromDescriptor` we use `dladdr` to get info on the the
current address.  `dladdr` returns 0 if it failed.
During testing on Linux this returned 0 to indicate failure, and
populated the `info` structure with a NULL pointer which was
dereferenced later.

This patch checks for `dladdr` returning 0, and in that case returns 0
from `GetGlobalSizeFromDescriptor` to indicate failure of identifying
the address.

This occurs when `GetModuleNameAndOffsetForPC` succeeds for some address
not in a dynamically loaded library.  One example is when the found
"module" is '[stack]' having come from parsing /proc/self/maps.

Cherry-pick from 83ac18205ec69a00ac2be3b603bc3a61293fbe89.

Differential Revision: https://reviews.llvm.org/D91344
This commit is contained in:
Matthew Malcomson 2020-11-25 16:31:35 +00:00
parent 1ee3d1ef10
commit 8eb12742e8
1 changed files with 2 additions and 1 deletions
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3
libsanitizer/hwasan/hwasan_report.cpp
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@ -254,7 +254,8 @@ static bool TagsEqual(tag_t tag, tag_t *tag_ptr) {
static uptr GetGlobalSizeFromDescriptor(uptr ptr) {
// Find the ELF object that this global resides in.
Dl_info info;
dladdr(reinterpret_cast<void *>(ptr), &info);
if (dladdr(reinterpret_cast<void *>(ptr), &info) == 0)
return 0;
auto *ehdr = reinterpret_cast<const ElfW(Ehdr) *>(info.dli_fbase);
auto *phdr_begin = reinterpret_cast<const ElfW(Phdr) *>(
reinterpret_cast<const u8 *>(ehdr) + ehdr->e_phoff);