From 0301ce1486b1450f219202677f30d0fa97335419 Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Tue, 17 Oct 2017 16:43:47 +1030 Subject: [PATCH] PR22306, Invalid free() in slurp_symtab() PR 22306 * aoutx.h (aout_get_external_symbols): Handle stringsize of zero, and error for any other size that doesn't cover the header word. Upstream-Status: Backport Affects: <= 2.29.1 CVE: CVE-2017-16827 Signed-off-by: Armin Kuster --- bfd/ChangeLog | 6 ++++++ bfd/aoutx.h | 45 ++++++++++++++++++++++++++++++--------------- 2 files changed, 36 insertions(+), 15 deletions(-) Index: git/bfd/aoutx.h =================================================================== --- git.orig/bfd/aoutx.h +++ git/bfd/aoutx.h @@ -1352,27 +1352,42 @@ aout_get_external_symbols (bfd *abfd) || bfd_bread ((void *) string_chars, amt, abfd) != amt) return FALSE; stringsize = GET_WORD (abfd, string_chars); + if (stringsize == 0) + stringsize = 1; + else if (stringsize < BYTES_IN_WORD + || (size_t) stringsize != stringsize) + { + bfd_set_error (bfd_error_bad_value); + return FALSE; + } #ifdef USE_MMAP - if (! bfd_get_file_window (abfd, obj_str_filepos (abfd), stringsize, - &obj_aout_string_window (abfd), TRUE)) - return FALSE; - strings = (char *) obj_aout_string_window (abfd).data; -#else - strings = (char *) bfd_malloc (stringsize + 1); - if (strings == NULL) - return FALSE; - - /* Skip space for the string count in the buffer for convenience - when using indexes. */ - amt = stringsize - BYTES_IN_WORD; - if (bfd_bread (strings + BYTES_IN_WORD, amt, abfd) != amt) + if (stringsize >= BYTES_IN_WORD) { - free (strings); - return FALSE; + if (! bfd_get_file_window (abfd, obj_str_filepos (abfd), stringsize, + &obj_aout_string_window (abfd), TRUE)) + return FALSE; + strings = (char *) obj_aout_string_window (abfd).data; } + else #endif + { + strings = (char *) bfd_malloc (stringsize); + if (strings == NULL) + return FALSE; + if (stringsize >= BYTES_IN_WORD) + { + /* Keep the string count in the buffer for convenience + when indexing with e_strx. */ + amt = stringsize - BYTES_IN_WORD; + if (bfd_bread (strings + BYTES_IN_WORD, amt, abfd) != amt) + { + free (strings); + return FALSE; + } + } + } /* Ensure that a zero index yields an empty string. */ strings[0] = '\0'; Index: git/bfd/ChangeLog =================================================================== --- git.orig/bfd/ChangeLog +++ git/bfd/ChangeLog @@ -1,3 +1,9 @@ +2017-10-17 Alan Modra + + PR 22306 + * aoutx.h (aout_get_external_symbols): Handle stringsize of zero, + and error for any other size that doesn't cover the header word. + 2017-11-01 Nick Clifton PR 22376