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[PATCH] readelf: handle corrupted chains better
- From: Mike Frysinger <vapier at gentoo dot org>
- To: binutils at sourceware dot org
- Date: Tue, 24 Feb 2015 01:56:46 -0500
- Subject: [PATCH] readelf: handle corrupted chains better
- Authentication-results: sourceware.org; auth=none
The current chain walker tries to protect itself against loops, by only
works with loops of length 1: a chain that points to itself. If you have
a chain longer than that (3->4->3->4->...), readelf will still hang.
Since we know the max length of the chain, simply abort when we've walked
more times than that. The only way that could have happened is if there
was a loop.
2015-02-24 Mike Frysinger <vapier@gentoo.org>
PR binutils/17531
* readelf.c (process_symbol_table): Declare chained. Increment it
in every loop. Abort when chained is larger than nchains. Move
error check outside of chain loop.
---
binutils/readelf.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 66b8f98..f1322d3 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -10722,6 +10722,7 @@ process_symbol_table (FILE * file)
unsigned long maxlength = 0;
unsigned long nzero_counts = 0;
unsigned long nsyms = 0;
+ unsigned long chained;
printf (_("\nHistogram for bucket list length (total of %lu buckets):\n"),
(unsigned long) nbuckets);
@@ -10736,21 +10737,23 @@ process_symbol_table (FILE * file)
printf (_(" Length Number %% of total Coverage\n"));
for (hn = 0; hn < nbuckets; ++hn)
{
- for (si = buckets[hn]; si > 0 && si < nchains && si < nbuckets; si = chains[si])
+ for (si = buckets[hn], chained = 0;
+ si > 0 && si < nchains && si < nbuckets && chained <= nchains;
+ si = chains[si], ++chained)
{
++nsyms;
if (maxlength < ++lengths[hn])
++maxlength;
-
- /* PR binutils/17531: A corrupt binary could contain broken
- histogram data. Do not go into an infinite loop trying
- to process it. */
- if (chains[si] == si)
- {
- error (_("histogram chain links to itself\n"));
- break;
- }
}
+
+ /* PR binutils/17531: A corrupt binary could contain broken
+ histogram data. Do not go into an infinite loop trying
+ to process it. */
+ if (chained > nchains)
+ {
+ error (_("histogram chain is corrupt\n"));
+ break;
+ }
}
counts = (unsigned long *) calloc (maxlength + 1, sizeof (*counts));
--
2.3.0