From 961a2851324561caed579764ffbee3db82b32829 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Fri, 21 Jun 2024 21:39:33 +0300 Subject: [PATCH] build-id: require program headers to be right after ELF header Neither ELF spec not ELF loader require program header to be placed right after ELF header, but build-id code very much assumes such placement: See find_get_page(vma->vm_file->f_mapping, 0); line and checks against PAGE_SIZE. Returns errors for now until someone rewrites build-id parser to be more inline with load_elf_binary(). Link: https://lkml.kernel.org/r/d58bc281-6ca7-467a-9a64-40fa214bd63e@p183 Signed-off-by: Alexey Dobriyan Reviewed-by: Jiri Olsa Signed-off-by: Andrew Morton --- lib/buildid.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/lib/buildid.c b/lib/buildid.c index 7954dd92e36c..e02b5507418b 100644 --- a/lib/buildid.c +++ b/lib/buildid.c @@ -73,6 +73,13 @@ static int get_build_id_32(const void *page_addr, unsigned char *build_id, Elf32_Phdr *phdr; int i; + /* + * FIXME + * Neither ELF spec nor ELF loader require that program headers + * start immediately after ELF header. + */ + if (ehdr->e_phoff != sizeof(Elf32_Ehdr)) + return -EINVAL; /* only supports phdr that fits in one page */ if (ehdr->e_phnum > (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr)) @@ -98,6 +105,13 @@ static int get_build_id_64(const void *page_addr, unsigned char *build_id, Elf64_Phdr *phdr; int i; + /* + * FIXME + * Neither ELF spec nor ELF loader require that program headers + * start immediately after ELF header. + */ + if (ehdr->e_phoff != sizeof(Elf64_Ehdr)) + return -EINVAL; /* only supports phdr that fits in one page */ if (ehdr->e_phnum > (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))