From: George Rimar Date: Thu, 10 Oct 2019 13:26:26 +0000 (+0000) Subject: [llvm-readelf] - Do not enter an infinite loop when printing histogram. X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d064df308ff87622a5320bebec8ce7beaca61b1a;p=llvm [llvm-readelf] - Do not enter an infinite loop when printing histogram. This is similar to D68086. We are entering an infinite loop when dumping a histogram for a specially crafted .hash section with a loop in a chain. Differential revision: https://reviews.llvm.org/D68771 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@374344 91177308-0d34-0410-b5e6-96231b3b80d8 --- diff --git a/test/tools/llvm-readobj/elf-hash-histogram.test b/test/tools/llvm-readobj/elf-hash-histogram.test index 13aa5137301..e0c29d15abc 100644 --- a/test/tools/llvm-readobj/elf-hash-histogram.test +++ b/test/tools/llvm-readobj/elf-hash-histogram.test @@ -1,27 +1,70 @@ -RUN: llvm-readelf --elf-hash-histogram %p/Inputs/gnuhash.so.elf-ppc64 \ -RUN: | FileCheck %s -check-prefix PPC64GNU -RUN: llvm-readelf --elf-hash-histogram %p/Inputs/gnuhash.so.elf-x86_64 \ -RUN: | FileCheck %s -check-prefix X86GNU -RUN: llvm-readelf --elf-hash-histogram %p/Inputs/got-plt.exe.elf-mipsel \ -RUN: | FileCheck %s -check-prefix SYSV +# RUN: llvm-readelf --elf-hash-histogram %p/Inputs/gnuhash.so.elf-ppc64 \ +# RUN: | FileCheck %s -check-prefix PPC64GNU +# RUN: llvm-readelf --elf-hash-histogram %p/Inputs/gnuhash.so.elf-x86_64 \ +# RUN: | FileCheck %s -check-prefix X86GNU +# RUN: llvm-readelf --elf-hash-histogram %p/Inputs/got-plt.exe.elf-mipsel \ +# RUN: | FileCheck %s -check-prefix SYSV -PPC64GNU: Histogram for `.gnu.hash' bucket list length (total of 3 buckets) -PPC64GNU-NEXT: Length Number % of total Coverage -PPC64GNU-NEXT: 0 1 ( 33.3%) 0.0% -PPC64GNU-NEXT: 1 1 ( 33.3%) 25.0% -PPC64GNU-NEXT: 2 0 ( 0.0%) 25.0% -PPC64GNU-NEXT: 3 1 ( 33.3%) 100.0% +# PPC64GNU: Histogram for `.gnu.hash' bucket list length (total of 3 buckets) +# PPC64GNU-NEXT: Length Number % of total Coverage +# PPC64GNU-NEXT: 0 1 ( 33.3%) 0.0% +# PPC64GNU-NEXT: 1 1 ( 33.3%) 25.0% +# PPC64GNU-NEXT: 2 0 ( 0.0%) 25.0% +# PPC64GNU-NEXT: 3 1 ( 33.3%) 100.0% -X86GNU: Histogram for `.gnu.hash' bucket list length (total of 3 buckets) -X86GNU-NEXT: Length Number % of total Coverage -X86GNU-NEXT: 0 1 ( 33.3%) 0.0% -X86GNU-NEXT: 1 1 ( 33.3%) 25.0% -X86GNU-NEXT: 2 0 ( 0.0%) 25.0% -X86GNU-NEXT: 3 1 ( 33.3%) 100.0% +# X86GNU: Histogram for `.gnu.hash' bucket list length (total of 3 buckets) +# X86GNU-NEXT: Length Number % of total Coverage +# X86GNU-NEXT: 0 1 ( 33.3%) 0.0% +# X86GNU-NEXT: 1 1 ( 33.3%) 25.0% +# X86GNU-NEXT: 2 0 ( 0.0%) 25.0% +# X86GNU-NEXT: 3 1 ( 33.3%) 100.0% -SYSV: Histogram for bucket list length (total of 3 buckets) -SYSV-NEXT: Length Number % of total Coverage -SYSV-NEXT: 0 0 ( 0.0%) 0.0% -SYSV-NEXT: 1 0 ( 0.0%) 0.0% -SYSV-NEXT: 2 2 ( 66.7%) 57.1% -SYSV-NEXT: 3 1 ( 33.3%) 100.0% +# SYSV: Histogram for bucket list length (total of 3 buckets) +# SYSV-NEXT: Length Number % of total Coverage +# SYSV-NEXT: 0 0 ( 0.0%) 0.0% +# SYSV-NEXT: 1 0 ( 0.0%) 0.0% +# SYSV-NEXT: 2 2 ( 66.7%) 57.1% +# SYSV-NEXT: 3 1 ( 33.3%) 100.0% + +## Show that we report a warning for a hash table which contains an entry of +## the bucket array pointing to a cycle. + +# RUN: yaml2obj %s -o %t.o +# RUN: llvm-readelf --elf-hash-histogram 2>&1 %t.o | FileCheck -DFILE=%t.o %s --check-prefix BROKEN + +# BROKEN: warning: '[[FILE]]': .hash section is invalid: bucket 1: a cycle was detected in the linked chain +# BROKEN: Histogram for bucket list length (total of 1 buckets) +# BROKEN-NEXT: Length Number % of total Coverage +# BROKEN-NEXT: 0 0 ( 0.0%) 0.0% +# BROKEN-NEXT: 1 1 (100.0%) 100.0% + +--- !ELF +FileHeader: + Class: ELFCLASS32 + Data: ELFDATA2LSB + Type: ET_REL + Machine: EM_386 +Sections: + - Name: .hash + Type: SHT_HASH + Link: .dynsym + Bucket: [ 1 ] + Chain: [ 0, 1 ] + - Name: .dynamic + Type: SHT_DYNAMIC + Flags: [ SHF_ALLOC ] + Entries: +## llvm-readelf will read the hash table from the file offset +## p_offset + (p_vaddr - DT_HASH) = p_offset + (0 - 0) = p_offset, +## which is the start of PT_LOAD, i.e. the file offset of .hash. + - Tag: DT_HASH + Value: 0x0 + - Tag: DT_NULL + Value: 0 +DynamicSymbols: + - Name: foo +ProgramHeaders: + - Type: PT_LOAD + Sections: + - Section: .hash + - Section: .dynamic diff --git a/tools/llvm-readobj/ELFDumper.cpp b/tools/llvm-readobj/ELFDumper.cpp index 4e9cf213174..135624539ae 100644 --- a/tools/llvm-readobj/ELFDumper.cpp +++ b/tools/llvm-readobj/ELFDumper.cpp @@ -3968,9 +3968,21 @@ void GNUStyle::printHashHistogram(const ELFFile *Obj) { // Go over all buckets and and note chain lengths of each bucket (total // unique chain lengths). for (size_t B = 0; B < NBucket; B++) { - for (size_t C = Buckets[B]; C > 0 && C < NChain; C = Chains[C]) + std::vector Visited(NChain); + for (size_t C = Buckets[B]; C < NChain; C = Chains[C]) { + if (C == ELF::STN_UNDEF) + break; + if (Visited[C]) { + reportWarning( + createError(".hash section is invalid: bucket " + Twine(C) + + ": a cycle was detected in the linked chain"), + this->FileName); + break; + } + Visited[C] = true; if (MaxChain <= ++ChainLen[B]) MaxChain++; + } TotalSyms += ChainLen[B]; }