From: Alan Modra <amodra@gmail.com>
To: binutils@sourceware.org
Subject: XCOFF archive sanity check
Date: Sun, 19 Mar 2023 22:23:04 +1030 [thread overview]
Message-ID: <ZBb3oOZ4J35lf6nK@squeak.grove.modra.org> (raw)
XCOFF archive elements are in a linked list. Add a little more sanity
checking. This of course doesn't stop the fuzzers finding a way to
make a loop, but this check is cheap.
* coff-rs6000.c (_bfd_xcoff_openr_next_archived_file): Sanity
check that next element isn't pointing back to the header.
diff --git a/bfd/coff-rs6000.c b/bfd/coff-rs6000.c
index 4b7b5d315df..735d434951e 100644
--- a/bfd/coff-rs6000.c
+++ b/bfd/coff-rs6000.c
@@ -1714,8 +1714,11 @@ _bfd_xcoff_openr_next_archived_file (bfd *archive, bfd *last_file)
laststart -= SIZEOF_AR_HDR + arel->extra_size;
}
- /* Sanity check that we aren't pointing into the previous element. */
- if (filestart != 0 && filestart >= laststart && filestart < lastend)
+ /* Sanity check that we aren't pointing into the previous element,
+ or into the header. */
+ if (filestart != 0
+ && (filestart < SIZEOF_AR_FILE_HDR
+ || (filestart >= laststart && filestart < lastend)))
{
bfd_set_error (bfd_error_malformed_archive);
return NULL;
@@ -1747,8 +1750,11 @@ _bfd_xcoff_openr_next_archived_file (bfd *archive, bfd *last_file)
laststart -= SIZEOF_AR_HDR_BIG + arel->extra_size;
}
- /* Sanity check that we aren't pointing into the previous element. */
- if (filestart != 0 && filestart >= laststart && filestart < lastend)
+ /* Sanity check that we aren't pointing into the previous element
+ or into the header. */
+ if (filestart != 0
+ && (filestart < SIZEOF_AR_FILE_HDR_BIG
+ || (filestart >= laststart && filestart < lastend)))
{
bfd_set_error (bfd_error_malformed_archive);
return NULL;
--
Alan Modra
Australia Development Lab, IBM
reply other threads:[~2023-03-19 11:53 UTC|newest]
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