From nobody Wed Apr 06 03:04:51 2022 X-Original-To: dev-commits-src-branches@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id D68961A851E1; Wed, 6 Apr 2022 03:04:52 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4KY8WS06q6z4dvZ; Wed, 6 Apr 2022 03:04:51 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1649214292; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=qOJ9S9RfAXKGn0aOSI6zXSiZe6FL0DMrc4BHZHDmluY=; b=oSP6LYHwgq+16fq4llknzmurZxKAK3m+AePnLC/tlN9ip3tAwlvzjM7KtvlPAoEtOh8wdE dU/BqkW1Wu43Lft1PvduOufaye2c3AdzYNSKvpZizS0UKlUOSqviGTnv3WycVCxiKkVaWF vHUiEj+qYCbIwwbKWpXux6J9QPcKwb+weQZZ2P+my1XY/rkTwxR7pPT9P6EwCb+Lgbawgs QcjLfnbCnJUpCEw8WXvNlEDUrCaJcePT7RSJ5vxDsExTfVwW1Mg38OLRxEhQZ2A8glSNoV HDA5G0YKkI3afcoDC3jerLO6+2nbIeIeQQMvj5GCJHg739ucegozia+GfX3tPA== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 81F78130FA; Wed, 6 Apr 2022 03:04:51 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 23634pZK035226; Wed, 6 Apr 2022 03:04:51 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 23634pIM035225; Wed, 6 Apr 2022 03:04:51 GMT (envelope-from git) Date: Wed, 6 Apr 2022 03:04:51 GMT Message-Id: <202204060304.23634pIM035225@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Ed Maste Subject: git: 49dcaa348546 - releng/12.3 - zlib: Fix a bug that can crash deflate on some input when using Z_FIXED. List-Id: Commits to the stable branches of the FreeBSD src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-branches List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-branches@freebsd.org X-BeenThere: dev-commits-src-branches@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: emaste X-Git-Repository: src X-Git-Refname: refs/heads/releng/12.3 X-Git-Reftype: branch X-Git-Commit: 49dcaa348546a9aeacee965fc6cadc3c89d29bf4 Auto-Submitted: auto-generated ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1649214292; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=qOJ9S9RfAXKGn0aOSI6zXSiZe6FL0DMrc4BHZHDmluY=; b=PwU8kZx08scj0zPQ2VwovtwT6Gvv66hYtY4tv+UBIclpYk6aa8iOxm+aoMy/jVy7YcxzOZ cenU48jMnKOKhiTGsd4NbeTv7II/85qiiwQerk98WV6Wfe/YttBfy7jUtXxyBeP5wYTNbc KovdqC0AIRXpEsnWYiCXzLSzEkZ9VoMHMIe3N0sv2YdNkKqK4DzRl8XDrIUVS+V9TX0e9a 2bytN1JwwK0mVRkIP9CdWqua3h5puP0Eg6KxqRlDS9KOKtXqvQb8mEoNuOzCVi9fgfPAAq LHE7VSbnw+qg7RLtr7q1jzhDu+SPEUYWq+bcUjpehOAhM65fqCr6Ibqxbffq7Q== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1649214292; a=rsa-sha256; cv=none; b=OSth19h3QZzf5YHV7Xspz1T4vb1IpVIImDRHF3pT0biqD7Ey+afr0gDCKYAy4QN5EL/JFG BIZBaONSNODG2NElizZFzXWL/lAiazL7ex6KYuEPxZ2GOtCUVvZWcllG78qG/Qo0xTQsXH igWTCpM6vleFOOrlcdsOIh8Yp8vntehcAcLK7hq45ZHkWH2wSklFyHySStSPstxDtObER1 5Ha7CHh5wArxtsLldEZeTeGhNcwiMZFChmwxOXpnsyHOjizDOqYC85uvs4H471vkq7mzv7 QpQtnCUa4gSGdeyQ/ex/ROVfC99Z2QKgU83AwnC0L7wIkdivBuX2Ape8s+VMSQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N The branch releng/12.3 has been updated by emaste: URL: https://cgit.FreeBSD.org/src/commit/?id=49dcaa348546a9aeacee965fc6cadc3c89d29bf4 commit 49dcaa348546a9aeacee965fc6cadc3c89d29bf4 Author: Ed Maste AuthorDate: 2022-04-05 23:34:30 +0000 Commit: Ed Maste CommitDate: 2022-04-05 23:34:30 +0000 zlib: Fix a bug that can crash deflate on some input when using Z_FIXED. Cherry picked from zlib 5c44459c3b28a9bd3283aaceab7c615f8020c531: This bug was reported by Danilo Ramos of Eideticom, Inc. It has lain in wait 13 years before being found! The bug was introduced in zlib 1.2.2.2, with the addition of the Z_FIXED option. That option forces the use of fixed Huffman codes. For rare inputs with a large number of distant matches, the pending buffer into which the compressed data is written can overwrite the distance symbol table which it overlays. That results in corrupted output due to invalid distances, and can result in out-of-bound accesses, crashing the application. The fix here combines the distance buffer and literal/length buffers into a single symbol buffer. Now three bytes of pending buffer space are opened up for each literal or length/distance pair consumed, instead of the previous two bytes. This assures that the pending buffer cannot overwrite the symbol table, since the maximum fixed code compressed length/distance is 31 bits, and since there are four bytes of pending space for every three bytes of symbol space. Approved by: so Security: CVE-2018-25032 Security: FreeBSD-SA-22:08.zlib --- sys/contrib/zlib/deflate.c | 74 +++++++++++++++++++++++++++++++++------------- sys/contrib/zlib/deflate.h | 25 +++++++--------- sys/contrib/zlib/trees.c | 50 +++++++++---------------------- 3 files changed, 79 insertions(+), 70 deletions(-) diff --git a/sys/contrib/zlib/deflate.c b/sys/contrib/zlib/deflate.c index 00c6e05c7769..50e8eb84c429 100644 --- a/sys/contrib/zlib/deflate.c +++ b/sys/contrib/zlib/deflate.c @@ -255,11 +255,6 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, int wrap = 1; static const char my_version[] = ZLIB_VERSION; - ushf *overlay; - /* We overlay pending_buf and d_buf+l_buf. This works since the average - * output size for (length,distance) codes is <= 24 bits. - */ - if (version == Z_NULL || version[0] != my_version[0] || stream_size != sizeof(z_stream)) { return Z_VERSION_ERROR; @@ -329,9 +324,47 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ - overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); - s->pending_buf = (uchf *) overlay; - s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); + /* We overlay pending_buf and sym_buf. This works since the average size + * for length/distance pairs over any compressed block is assured to be 31 + * bits or less. + * + * Analysis: The longest fixed codes are a length code of 8 bits plus 5 + * extra bits, for lengths 131 to 257. The longest fixed distance codes are + * 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest + * possible fixed-codes length/distance pair is then 31 bits total. + * + * sym_buf starts one-fourth of the way into pending_buf. So there are + * three bytes in sym_buf for every four bytes in pending_buf. Each symbol + * in sym_buf is three bytes -- two for the distance and one for the + * literal/length. As each symbol is consumed, the pointer to the next + * sym_buf value to read moves forward three bytes. From that symbol, up to + * 31 bits are written to pending_buf. The closest the written pending_buf + * bits gets to the next sym_buf symbol to read is just before the last + * code is written. At that time, 31*(n-2) bits have been written, just + * after 24*(n-2) bits have been consumed from sym_buf. sym_buf starts at + * 8*n bits into pending_buf. (Note that the symbol buffer fills when n-1 + * symbols are written.) The closest the writing gets to what is unread is + * then n+14 bits. Here n is lit_bufsize, which is 16384 by default, and + * can range from 128 to 32768. + * + * Therefore, at a minimum, there are 142 bits of space between what is + * written and what is read in the overlain buffers, so the symbols cannot + * be overwritten by the compressed data. That space is actually 139 bits, + * due to the three-bit fixed-code block header. + * + * That covers the case where either Z_FIXED is specified, forcing fixed + * codes, or when the use of fixed codes is chosen, because that choice + * results in a smaller compressed block than dynamic codes. That latter + * condition then assures that the above analysis also covers all dynamic + * blocks. A dynamic-code block will only be chosen to be emitted if it has + * fewer bits than a fixed-code block would for the same set of symbols. + * Therefore its average symbol length is assured to be less than 31. So + * the compressed data for a dynamic block also cannot overwrite the + * symbols from which it is being constructed. + */ + + s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, 4); + s->pending_buf_size = (ulg)s->lit_bufsize * 4; if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || s->pending_buf == Z_NULL) { @@ -340,8 +373,12 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy, deflateEnd (strm); return Z_MEM_ERROR; } - s->d_buf = overlay + s->lit_bufsize/sizeof(ush); - s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; + s->sym_buf = s->pending_buf + s->lit_bufsize; + s->sym_end = (s->lit_bufsize - 1) * 3; + /* We avoid equality with lit_bufsize*3 because of wraparound at 64K + * on 16 bit machines and because stored blocks are restricted to + * 64K-1 bytes. + */ s->level = level; s->strategy = strategy; @@ -552,7 +589,7 @@ int ZEXPORT deflatePrime (strm, bits, value) if (deflateStateCheck(strm)) return Z_STREAM_ERROR; s = strm->state; - if ((Bytef *)(s->d_buf) < s->pending_out + ((Buf_size + 7) >> 3)) + if (s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3)) return Z_BUF_ERROR; do { put = Buf_size - s->bi_valid; @@ -1111,7 +1148,6 @@ int ZEXPORT deflateCopy (dest, source) #else deflate_state *ds; deflate_state *ss; - ushf *overlay; if (deflateStateCheck(source) || dest == Z_NULL) { @@ -1131,8 +1167,7 @@ int ZEXPORT deflateCopy (dest, source) ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); - overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); - ds->pending_buf = (uchf *) overlay; + ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, 4); if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || ds->pending_buf == Z_NULL) { @@ -1146,8 +1181,7 @@ int ZEXPORT deflateCopy (dest, source) zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); - ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); - ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; + ds->sym_buf = ds->pending_buf + ds->lit_bufsize; ds->l_desc.dyn_tree = ds->dyn_ltree; ds->d_desc.dyn_tree = ds->dyn_dtree; @@ -1915,7 +1949,7 @@ local block_state deflate_fast(s, flush) FLUSH_BLOCK(s, 1); return finish_done; } - if (s->last_lit) + if (s->sym_next) FLUSH_BLOCK(s, 0); return block_done; } @@ -2046,7 +2080,7 @@ local block_state deflate_slow(s, flush) FLUSH_BLOCK(s, 1); return finish_done; } - if (s->last_lit) + if (s->sym_next) FLUSH_BLOCK(s, 0); return block_done; } @@ -2121,7 +2155,7 @@ local block_state deflate_rle(s, flush) FLUSH_BLOCK(s, 1); return finish_done; } - if (s->last_lit) + if (s->sym_next) FLUSH_BLOCK(s, 0); return block_done; } @@ -2160,7 +2194,7 @@ local block_state deflate_huff(s, flush) FLUSH_BLOCK(s, 1); return finish_done; } - if (s->last_lit) + if (s->sym_next) FLUSH_BLOCK(s, 0); return block_done; } diff --git a/sys/contrib/zlib/deflate.h b/sys/contrib/zlib/deflate.h index 23ecdd312bc0..d4cf1a98be4d 100644 --- a/sys/contrib/zlib/deflate.h +++ b/sys/contrib/zlib/deflate.h @@ -217,7 +217,7 @@ typedef struct internal_state { /* Depth of each subtree used as tie breaker for trees of equal frequency */ - uchf *l_buf; /* buffer for literals or lengths */ + uchf *sym_buf; /* buffer for distances and literals/lengths */ uInt lit_bufsize; /* Size of match buffer for literals/lengths. There are 4 reasons for @@ -239,13 +239,8 @@ typedef struct internal_state { * - I can't count above 4 */ - uInt last_lit; /* running index in l_buf */ - - ushf *d_buf; - /* Buffer for distances. To simplify the code, d_buf and l_buf have - * the same number of elements. To use different lengths, an extra flag - * array would be necessary. - */ + uInt sym_next; /* running index in sym_buf */ + uInt sym_end; /* symbol table full when sym_next reaches this */ ulg opt_len; /* bit length of current block with optimal trees */ ulg static_len; /* bit length of current block with static trees */ @@ -325,20 +320,22 @@ void ZLIB_INTERNAL _tr_stored_block OF((deflate_state *s, charf *buf, # define _tr_tally_lit(s, c, flush) \ { uch cc = (c); \ - s->d_buf[s->last_lit] = 0; \ - s->l_buf[s->last_lit++] = cc; \ + s->sym_buf[s->sym_next++] = 0; \ + s->sym_buf[s->sym_next++] = 0; \ + s->sym_buf[s->sym_next++] = cc; \ s->dyn_ltree[cc].Freq++; \ - flush = (s->last_lit == s->lit_bufsize-1); \ + flush = (s->sym_next == s->sym_end); \ } # define _tr_tally_dist(s, distance, length, flush) \ { uch len = (uch)(length); \ ush dist = (ush)(distance); \ - s->d_buf[s->last_lit] = dist; \ - s->l_buf[s->last_lit++] = len; \ + s->sym_buf[s->sym_next++] = dist; \ + s->sym_buf[s->sym_next++] = dist >> 8; \ + s->sym_buf[s->sym_next++] = len; \ dist--; \ s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \ s->dyn_dtree[d_code(dist)].Freq++; \ - flush = (s->last_lit == s->lit_bufsize-1); \ + flush = (s->sym_next == s->sym_end); \ } #else # define _tr_tally_lit(s, c, flush) flush = _tr_tally(s, 0, c) diff --git a/sys/contrib/zlib/trees.c b/sys/contrib/zlib/trees.c index 50cf4b4571cf..5f89d056ef96 100644 --- a/sys/contrib/zlib/trees.c +++ b/sys/contrib/zlib/trees.c @@ -416,7 +416,7 @@ local void init_block(s) s->dyn_ltree[END_BLOCK].Freq = 1; s->opt_len = s->static_len = 0L; - s->last_lit = s->matches = 0; + s->sym_next = s->matches = 0; } #define SMALLEST 1 @@ -947,7 +947,7 @@ void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, - s->last_lit)); + s->sym_next / 3)); if (static_lenb <= opt_lenb) opt_lenb = static_lenb; @@ -1016,8 +1016,9 @@ int ZLIB_INTERNAL _tr_tally (s, dist, lc) unsigned dist; /* distance of matched string */ unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ { - s->d_buf[s->last_lit] = (ush)dist; - s->l_buf[s->last_lit++] = (uch)lc; + s->sym_buf[s->sym_next++] = dist; + s->sym_buf[s->sym_next++] = dist >> 8; + s->sym_buf[s->sym_next++] = lc; if (dist == 0) { /* lc is the unmatched char */ s->dyn_ltree[lc].Freq++; @@ -1032,30 +1033,7 @@ int ZLIB_INTERNAL _tr_tally (s, dist, lc) s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; s->dyn_dtree[d_code(dist)].Freq++; } - -#ifdef TRUNCATE_BLOCK - /* Try to guess if it is profitable to stop the current block here */ - if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { - /* Compute an upper bound for the compressed length */ - ulg out_length = (ulg)s->last_lit*8L; - ulg in_length = (ulg)((long)s->strstart - s->block_start); - int dcode; - for (dcode = 0; dcode < D_CODES; dcode++) { - out_length += (ulg)s->dyn_dtree[dcode].Freq * - (5L+extra_dbits[dcode]); - } - out_length >>= 3; - Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", - s->last_lit, in_length, out_length, - 100L - out_length*100L/in_length)); - if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; - } -#endif - return (s->last_lit == s->lit_bufsize-1); - /* We avoid equality with lit_bufsize because of wraparound at 64K - * on 16 bit machines and because stored blocks are restricted to - * 64K-1 bytes. - */ + return (s->sym_next == s->sym_end); } /* =========================================================================== @@ -1068,13 +1046,14 @@ local void compress_block(s, ltree, dtree) { unsigned dist; /* distance of matched string */ int lc; /* match length or unmatched char (if dist == 0) */ - unsigned lx = 0; /* running index in l_buf */ + unsigned sx = 0; /* running index in sym_buf */ unsigned code; /* the code to send */ int extra; /* number of extra bits to send */ - if (s->last_lit != 0) do { - dist = s->d_buf[lx]; - lc = s->l_buf[lx++]; + if (s->sym_next != 0) do { + dist = s->sym_buf[sx++] & 0xff; + dist += (unsigned)(s->sym_buf[sx++] & 0xff) << 8; + lc = s->sym_buf[sx++]; if (dist == 0) { send_code(s, lc, ltree); /* send a literal byte */ Tracecv(isgraph(lc), (stderr," '%c' ", lc)); @@ -1099,11 +1078,10 @@ local void compress_block(s, ltree, dtree) } } /* literal or match pair ? */ - /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ - Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, - "pendingBuf overflow"); + /* Check that the overlay between pending_buf and sym_buf is ok: */ + Assert(s->pending < s->lit_bufsize + sx, "pendingBuf overflow"); - } while (lx < s->last_lit); + } while (sx < s->sym_next); send_code(s, END_BLOCK, ltree); }