From eff308af425b67093bab25f80f1ae950166bece1 Mon Sep 17 00:00:00 2001 From: Mark Adler Date: Sat, 30 Jul 2022 15:51:11 -0700 Subject: [PATCH] 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. (Ref: https://github.com/madler/zlib/commit/eff308af4) --- inflate.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- zlib-1.2.11.dfsg.orig/inflate.c +++ zlib-1.2.11.dfsg/inflate.c @@ -758,9 +758,10 @@ int flush; copy = state->length; if (copy > have) copy = have; if (copy) { + len = state->head->extra_len - state->length; 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_max) { zmemcpy(state->head->extra + len, next, len + copy > state->head->extra_max ? state->head->extra_max - len : copy);