From bbabbae114f6d16dacdc1ad8f6f04b95fb6b17eb Mon Sep 17 00:00:00 2001 From: Nadeem Vawda Date: Sun, 28 Aug 2011 11:23:57 +0200 Subject: [PATCH] Issue #12839: Fix crash in zlib module due to version mismatch. If the version of zlib used to compile the zlib module is incompatible with the one that is actually linked in, then calls into zlib will fail. This can leave attributes of the z_stream uninitialized, so we must take care to avoid segfaulting by trying to use an invalid pointer. Fix by Richard M. Tew. --- Misc/ACKS | 1 + Misc/NEWS | 3 +++ Modules/zlibmodule.c | 8 +++++++- 3 files changed, 11 insertions(+), 1 deletion(-) diff --git a/Misc/ACKS b/Misc/ACKS index cdae287ddae..e728c511e13 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -813,6 +813,7 @@ Monty Taylor Amy Taylor Anatoly Techtonik Mikhail Terekhov +Richard M. Tew Tobias Thelen James Thomas Robin Thomas diff --git a/Misc/NEWS b/Misc/NEWS index e7faa4e117d..3709142c8fe 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -40,6 +40,9 @@ Core and Builtins Library ------- +- Issue #12839: Fix crash in zlib module due to version mismatch. + Fix by Richard M. Tew. + - Issue #12786: Set communication pipes used by subprocess.Popen CLOEXEC to avoid them being inherited by other subprocesses. diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c index bd6d6e256bc..035aa8e085d 100644 --- a/Modules/zlibmodule.c +++ b/Modules/zlibmodule.c @@ -72,7 +72,13 @@ typedef struct static void zlib_error(z_stream zst, int err, char *msg) { - const char *zmsg = zst.msg; + const char *zmsg = Z_NULL; + /* In case of a version mismatch, zst.msg won't be initialized. + Check for this case first, before looking at zst.msg. */ + if (err == Z_VERSION_ERROR) + zmsg = "library version mismatch"; + if (zmsg == Z_NULL) + zmsg = zst.msg; if (zmsg == Z_NULL) { switch (err) { case Z_BUF_ERROR: