From ec3df00224d4b396e2ac6586ab5d25f673caa4c2 Mon Sep 17 00:00:00 2001 From: Mark Adler Date: Wed, 30 Mar 2022 11:14:53 -0700 Subject: [PATCH] Correct incorrect inputs provided to the CRC functions. The previous releases of zlib were not sensitive to incorrect CRC inputs with bits set above the low 32. This commit restores that behavior, so that applications with such bugs will continue to operate as before. --- crc32.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/crc32.c b/crc32.c index a1bdce5c2..451887bc7 100644 --- a/crc32.c +++ b/crc32.c @@ -630,7 +630,7 @@ unsigned long ZEXPORT crc32_z(crc, buf, len) #endif /* DYNAMIC_CRC_TABLE */ /* Pre-condition the CRC */ - crc ^= 0xffffffff; + crc = (~crc) & 0xffffffff; /* Compute the CRC up to a word boundary. */ while (len && ((z_size_t)buf & 7) != 0) { @@ -749,7 +749,7 @@ unsigned long ZEXPORT crc32_z(crc, buf, len) #endif /* DYNAMIC_CRC_TABLE */ /* Pre-condition the CRC */ - crc ^= 0xffffffff; + crc = (~crc) & 0xffffffff; #ifdef W @@ -1077,7 +1077,7 @@ uLong ZEXPORT crc32_combine64(crc1, crc2, len2) #ifdef DYNAMIC_CRC_TABLE once(&made, make_crc_table); #endif /* DYNAMIC_CRC_TABLE */ - return multmodp(x2nmodp(len2, 3), crc1) ^ crc2; + return multmodp(x2nmodp(len2, 3), crc1) ^ (crc2 & 0xffffffff); } /* ========================================================================= */ @@ -1112,5 +1112,5 @@ uLong crc32_combine_op(crc1, crc2, op) uLong crc2; uLong op; { - return multmodp(op, crc1) ^ crc2; + return multmodp(op, crc1) ^ (crc2 & 0xffffffff); }