From 04f2902d9fadb2b8221162247412fb2c4667d95e Mon Sep 17 00:00:00 2001 From: Ulrich Drepper Date: Thu, 18 Mar 2010 13:15:27 -0700 Subject: [PATCH] Future safety in checking ELF header. If we should use further fields in the e_ident array in the ELF header of files we want zero to mean the default. Enforce zero for now so that non-optional features indicated by nonzero values are not go unnoticed when using an old dynamic linker. --- ChangeLog | 6 ++++++ elf/dl-load.c | 10 ++++++++-- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/ChangeLog b/ChangeLog index 92b6a91..9ff497d 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2010-03-18 Ulrich Drepper + + * elf/dl-load.c (open_verify): Extend expected to the full size of the + e_ident array. When loading, check that the fields in e_ident we don't + know are zero to allow future extensions. + 2010-03-18 H.J. Lu * sysdeps/i386/i686/multiarch/memcmp-ssse3.S: Update %xmm3 diff --git a/elf/dl-load.c b/elf/dl-load.c index 756816f..d8f9131 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -1573,7 +1573,7 @@ open_verify (const char *name, struct filebuf *fbp, struct link_map *loader, #elif defined MORE_ELF_HEADER_DATA MORE_ELF_HEADER_DATA; #endif - static const unsigned char expected[EI_PAD] = + static const unsigned char expected[EI_NIDENT] = { [EI_MAG0] = ELFMAG0, [EI_MAG1] = ELFMAG1, @@ -1657,7 +1657,10 @@ open_verify (const char *name, struct filebuf *fbp, struct link_map *loader, if (__builtin_expect (! VALID_ELF_HEADER (ehdr->e_ident, expected, EI_ABIVERSION) || !VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI], - ehdr->e_ident[EI_ABIVERSION]), + ehdr->e_ident[EI_ABIVERSION]) + || memcmp (&ehdr->e_ident[EI_PAD], + &expected[EI_PAD], + EI_NIDENT - EI_PAD) != 0, 0)) { /* Something is wrong. */ @@ -1701,6 +1704,9 @@ open_verify (const char *name, struct filebuf *fbp, struct link_map *loader, else if (!VALID_ELF_ABIVERSION (ehdr->e_ident[EI_OSABI], ehdr->e_ident[EI_ABIVERSION])) errstring = N_("ELF file ABI version invalid"); + else if (memcmp (&ehdr->e_ident[EI_PAD], &expected[EI_PAD], + EI_NIDENT - EI_PAD) != 0) + errstring = N_("nonzero padding in e_ident"); else /* Otherwise we don't know what went wrong. */ errstring = N_("internal error"); -- 2.7.4