Author: phosek Date: Wed Jan 23 19:04:42 2019 New Revision: 352016 URL: http://llvm.org/viewvc/llvm-project?rev=352016&view=rev Log: [libunwind] Don't abort if encoutering invalid .eh_frame_hdr
Recent Linux kernel release has introduced a bug as part of the ORC rollout where the vDSO has a valid .eh_frame section, but it's missing the .eh_frame_hdr section and GNU_EH_FRAME segment has zero size. This causes libunwind to abort which breaks programs that use libunwind. The other unwinder implementation (libgcc, non-gnu) instead silently bail out unless being compiled as debug. This change modifies libunwind to use the same strategy. Differential Revision: https://reviews.llvm.org/D57081 Modified: libunwind/trunk/src/AddressSpace.hpp libunwind/trunk/src/EHHeaderParser.hpp Modified: libunwind/trunk/src/AddressSpace.hpp URL: http://llvm.org/viewvc/llvm-project/libunwind/trunk/src/AddressSpace.hpp?rev=352016&r1=352015&r2=352016&view=diff ============================================================================== --- libunwind/trunk/src/AddressSpace.hpp (original) +++ libunwind/trunk/src/AddressSpace.hpp Wed Jan 23 19:04:42 2019 @@ -535,11 +535,11 @@ inline bool LocalAddressSpace::findUnwin #endif cbdata->sects->dwarf_index_section = eh_frame_hdr_start; cbdata->sects->dwarf_index_section_length = phdr->p_memsz; - EHHeaderParser<LocalAddressSpace>::decodeEHHdr( + found_hdr = EHHeaderParser<LocalAddressSpace>::decodeEHHdr( *cbdata->addressSpace, eh_frame_hdr_start, phdr->p_memsz, hdrInfo); - cbdata->sects->dwarf_section = hdrInfo.eh_frame_ptr; - found_hdr = true; + if (found_hdr) + cbdata->sects->dwarf_section = hdrInfo.eh_frame_ptr; } } Modified: libunwind/trunk/src/EHHeaderParser.hpp URL: http://llvm.org/viewvc/llvm-project/libunwind/trunk/src/EHHeaderParser.hpp?rev=352016&r1=352015&r2=352016&view=diff ============================================================================== --- libunwind/trunk/src/EHHeaderParser.hpp (original) +++ libunwind/trunk/src/EHHeaderParser.hpp Wed Jan 23 19:04:42 2019 @@ -35,7 +35,7 @@ public: uint8_t table_enc; }; - static void decodeEHHdr(A &addressSpace, pint_t ehHdrStart, pint_t ehHdrEnd, + static bool decodeEHHdr(A &addressSpace, pint_t ehHdrStart, pint_t ehHdrEnd, EHHeaderInfo &ehHdrInfo); static bool findFDE(A &addressSpace, pint_t pc, pint_t ehHdrStart, uint32_t sectionLength, @@ -52,12 +52,14 @@ private: }; template <typename A> -void EHHeaderParser<A>::decodeEHHdr(A &addressSpace, pint_t ehHdrStart, +bool EHHeaderParser<A>::decodeEHHdr(A &addressSpace, pint_t ehHdrStart, pint_t ehHdrEnd, EHHeaderInfo &ehHdrInfo) { pint_t p = ehHdrStart; uint8_t version = addressSpace.get8(p++); - if (version != 1) - _LIBUNWIND_ABORT("Unsupported .eh_frame_hdr version"); + if (version != 1) { + _LIBUNWIND_LOG0("Unsupported .eh_frame_hdr version"); + return false; + } uint8_t eh_frame_ptr_enc = addressSpace.get8(p++); uint8_t fde_count_enc = addressSpace.get8(p++); @@ -70,6 +72,8 @@ void EHHeaderParser<A>::decodeEHHdr(A &a ? 0 : addressSpace.getEncodedP(p, ehHdrEnd, fde_count_enc, ehHdrStart); ehHdrInfo.table = p; + + return true; } template <typename A> @@ -101,7 +105,9 @@ bool EHHeaderParser<A>::findFDE(A &addre pint_t ehHdrEnd = ehHdrStart + sectionLength; EHHeaderParser<A>::EHHeaderInfo hdrInfo; - EHHeaderParser<A>::decodeEHHdr(addressSpace, ehHdrStart, ehHdrEnd, hdrInfo); + if (!EHHeaderParser<A>::decodeEHHdr(addressSpace, ehHdrStart, ehHdrEnd, + hdrInfo)) + return false; size_t tableEntrySize = getTableEntrySize(hdrInfo.table_enc); pint_t tableEntry; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
