Prevent segfault in GDB when searching for architecture matches
Cherry-picked from upstream:
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commit;h=5d9bbb73c1df68741048c3d0f837b50c289ea608
This fixes gdb host crash when trying to read symbols from target.
While patch is arch-neutral, we could only reproduce the issue
for mips.
* format.c (struct bfd_preserve): New "build_id" field.
(bfd_preserve_save): Save "build_id".
(bfd_preserve_restore): Restore "build_id".
From https://sourceware.org/ml/gdb-patches/2016-09/msg00070.html :
Currently the "build_id" field of "struct bfd" is not preserved by
"struct bfd_preserve" when "bfd_check_format_matches" is going through
all target vectors trying to find a compatible target vector. This leads
to a segmentation fault in GDB.
Consider a case where one compatible target vector has already been
found (so the subset of bfd state is saved in struct bfd_preserve) and
then an attempt to find a better match fails after it has modified bfd's
build_id pointer. Since this attempt is failed, all its side effects
will be undone and all memory allocations done by this vector will be
free'd. This will eventually free the memory block that build_id pointer
is pointing to. This free'd block then gets reallocated and used for
storing something else -- leaving build_id pointing to incorrect
contents.
This patch adds "build_id" pointer to "struct bfd_preserve" so that it
will be preserved on success which can then be recoverable on failure.
Change-Id: I3e81c3a8a1d25869659bbf99bebe8b00062cea72
diff --git a/gdb-7.11/bfd/ChangeLog b/gdb-7.11/bfd/ChangeLog
index dc8b293..e4fc17e 100644
--- a/gdb-7.11/bfd/ChangeLog
+++ b/gdb-7.11/bfd/ChangeLog
@@ -1,3 +1,9 @@
+2016-09-14 Bhushan Attarde <bhushan.attarde@imgtec.com>
+
+ * format.c (struct bfd_preserve): New "build_id" field.
+ (bfd_preserve_save): Save "build_id".
+ (bfd_preserve_restore): Restore "build_id".
+
2016-02-10 Joel Brobecker <brobecker@adacore.com>
* development.sh (development): Set to false.
diff --git a/gdb-7.11/bfd/format.c b/gdb-7.11/bfd/format.c
index aad4dc2..129740f 100644
--- a/gdb-7.11/bfd/format.c
+++ b/gdb-7.11/bfd/format.c
@@ -104,6 +104,7 @@
struct bfd_section *section_last;
unsigned int section_count;
struct bfd_hash_table section_htab;
+ const struct bfd_build_id *build_id;
};
/* When testing an object for compatibility with a particular target
@@ -126,6 +127,7 @@
preserve->section_count = abfd->section_count;
preserve->section_htab = abfd->section_htab;
preserve->marker = bfd_alloc (abfd, 1);
+ preserve->build_id = abfd->build_id;
if (preserve->marker == NULL)
return FALSE;
@@ -158,6 +160,7 @@
abfd->sections = preserve->sections;
abfd->section_last = preserve->section_last;
abfd->section_count = preserve->section_count;
+ abfd->build_id = preserve->build_id;
/* bfd_release frees all memory more recently bfd_alloc'd than
its arg, as well as its arg. */
