git: 938108cf04f0 - releng/12.3 - zlib: Fix a bug when getting a gzip header extra field with inflate().

From: Ed Maste <emaste_at_FreeBSD.org>
Date: Tue, 30 Aug 2022 23:15:36 UTC
The branch releng/12.3 has been updated by emaste:

URL: https://cgit.FreeBSD.org/src/commit/?id=938108cf04f0e222455c97f7ef038cbb0411a1e7

commit 938108cf04f0e222455c97f7ef038cbb0411a1e7
Author:     Mark Adler <fork@madler.net>
AuthorDate: 2022-07-30 22:51:11 +0000
Commit:     Ed Maste <emaste@FreeBSD.org>
CommitDate: 2022-08-30 22:59:16 +0000

    zlib: Fix a bug when getting a gzip header extra field with inflate().
    
    If the extra field was larger than the space the user provided with
    inflateGetHeader(), and if multiple calls of inflate() delivered
    the extra header data, then there could be a buffer overflow of the
    provided space. This commit assures that provided space is not
    exceeded.
    
    (cherry picked from zlib commit eff308af425b67093bab25f80f1ae950166bece1)
    (cherry picked from zlib commit 1eb7682f845ac9e9bf9ae35bbfb3bad5dacbd91d)
    
    (cherry picked from commit dc3509f1aafcd966f3dd9226115cf94b691ff3c7)
    (cherry picked from commit 2969066f73fc67a614144ac09b9f3f5291937fed)
    (cherry picked from commit 72bc320879944fecae59e903381c33ab4d5e443b)
    (cherry picked from commit bd8faba77f6f8eb344ab4f5b44536dab87b2b05c)
    
    Approved by:    so
    Security:       CVE-2022-37434
---
 sys/contrib/zlib/inflate.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/sys/contrib/zlib/inflate.c b/sys/contrib/zlib/inflate.c
index ac333e8c2eda..cd018573dee8 100644
--- a/sys/contrib/zlib/inflate.c
+++ b/sys/contrib/zlib/inflate.c
@@ -759,8 +759,9 @@ int flush;
                 if (copy > have) copy = have;
                 if (copy) {
                     if (state->head != Z_NULL &&
-                        state->head->extra != Z_NULL) {
-                        len = state->head->extra_len - state->length;
+                        state->head->extra != Z_NULL &&
+                        (len = state->head->extra_len - state->length) <
+                            state->head->extra_max) {
                         zmemcpy(state->head->extra + len, next,
                                 len + copy > state->head->extra_max ?
                                 state->head->extra_max - len : copy);