Bad sh_off or sh_size could trigger a bad malloc or read. Sanity check the header values first before trying to malloc a huge buffer or reading any data that will certainly fail.
https://bugzilla.redhat.com/show_bug.cgi?id=1387584 Signed-off-by: Mark Wielaard <m...@redhat.com> --- libelf/ChangeLog | 5 +++++ libelf/elf_getdata.c | 11 +++++++++++ 2 files changed, 16 insertions(+) diff --git a/libelf/ChangeLog b/libelf/ChangeLog index 35af786..89546ab 100644 --- a/libelf/ChangeLog +++ b/libelf/ChangeLog @@ -1,3 +1,8 @@ +2016-10-21 Mark Wielaard <m...@redhat.com> + + * elf_getdata.c (__libelf_set_rawdata_wrlock): Sanity check + offset and size before trying to malloc and read data. + 2015-10-11 Akihiko Odaki <akihiko.odaki...@stu.hosei.ac.jp> * elf_getarsym.c (elf_getarsym): Open code rawmemchr when not diff --git a/libelf/elf_getdata.c b/libelf/elf_getdata.c index d1fafbf..97c503b 100644 --- a/libelf/elf_getdata.c +++ b/libelf/elf_getdata.c @@ -312,6 +312,17 @@ __libelf_set_rawdata_wrlock (Elf_Scn *scn) } else if (likely (elf->fildes != -1)) { + /* First see whether the information in the section header is + valid and it does not ask for too much. Check for unsigned + overflow. */ + if (unlikely (offset > elf->maximum_size + || elf->maximum_size - offset < size)) + { + /* Something is wrong. */ + __libelf_seterrno (ELF_E_INVALID_SECTION_HEADER); + return 1; + } + /* We have to read the data from the file. Allocate the needed memory. */ scn->rawdata_base = scn->rawdata.d.d_buf -- 1.8.3.1 _______________________________________________ elfutils-devel mailing list -- elfutils-devel@lists.fedorahosted.org To unsubscribe send an email to elfutils-devel-le...@lists.fedorahosted.org
