From 206a81c18401c0cde6e579164f752c4b147324ce Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Fri, 20 Jun 2014 22:00:53 -0700 Subject: lzo: properly check for overruns The lzo decompressor can, if given some really crazy data, possibly overrun some variable types. Modify the checking logic to properly detect overruns before they happen. Reported-by: "Don A. Bailey" Tested-by: "Don A. Bailey" Cc: stable Signed-off-by: Greg Kroah-Hartman diff --git a/lib/lzo/lzo1x_decompress_safe.c b/lib/lzo/lzo1x_decompress_safe.c index 569985d..8563081 100644 --- a/lib/lzo/lzo1x_decompress_safe.c +++ b/lib/lzo/lzo1x_decompress_safe.c @@ -19,11 +19,31 @@ #include #include "lzodefs.h" -#define HAVE_IP(x) ((size_t)(ip_end - ip) >= (size_t)(x)) -#define HAVE_OP(x) ((size_t)(op_end - op) >= (size_t)(x)) -#define NEED_IP(x) if (!HAVE_IP(x)) goto input_overrun -#define NEED_OP(x) if (!HAVE_OP(x)) goto output_overrun -#define TEST_LB(m_pos) if ((m_pos) < out) goto lookbehind_overrun +#define HAVE_IP(t, x) \ + (((size_t)(ip_end - ip) >= (size_t)(t + x)) && \ + (((t + x) >= t) && ((t + x) >= x))) + +#define HAVE_OP(t, x) \ + (((size_t)(op_end - op) >= (size_t)(t + x)) && \ + (((t + x) >= t) && ((t + x) >= x))) + +#define NEED_IP(t, x) \ + do { \ + if (!HAVE_IP(t, x)) \ + goto input_overrun; \ + } while (0) + +#define NEED_OP(t, x) \ + do { \ + if (!HAVE_OP(t, x)) \ + goto output_overrun; \ + } while (0) + +#define TEST_LB(m_pos) \ + do { \ + if ((m_pos) < out) \ + goto lookbehind_overrun; \ + } while (0) int lzo1x_decompress_safe(const unsigned char *in, size_t in_len, unsigned char *out, size_t *out_len) @@ -58,14 +78,14 @@ int lzo1x_decompress_safe(const unsigned char *in, size_t in_len, while (unlikely(*ip == 0)) { t += 255; ip++; - NEED_IP(1); + NEED_IP(1, 0); } t += 15 + *ip++; } t += 3; copy_literal_run: #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) - if (likely(HAVE_IP(t + 15) && HAVE_OP(t + 15))) { + if (likely(HAVE_IP(t, 15) && HAVE_OP(t, 15))) { const unsigned char *ie = ip + t; unsigned char *oe = op + t; do { @@ -81,8 +101,8 @@ copy_literal_run: } else #endif { - NEED_OP(t); - NEED_IP(t + 3); + NEED_OP(t, 0); + NEED_IP(t, 3); do { *op++ = *ip++; } while (--t > 0); @@ -95,7 +115,7 @@ copy_literal_run: m_pos -= t >> 2; m_pos -= *ip++ << 2; TEST_LB(m_pos); - NEED_OP(2); + NEED_OP(2, 0); op[0] = m_pos[0]; op[1] = m_pos[1]; op += 2; @@ -119,10 +139,10 @@ copy_literal_run: while (unlikely(*ip == 0)) { t += 255; ip++; - NEED_IP(1); + NEED_IP(1, 0); } t += 31 + *ip++; - NEED_IP(2); + NEED_IP(2, 0); } m_pos = op - 1; next = get_unaligned_le16(ip); @@ -137,10 +157,10 @@ copy_literal_run: while (unlikely(*ip == 0)) { t += 255; ip++; - NEED_IP(1); + NEED_IP(1, 0); } t += 7 + *ip++; - NEED_IP(2); + NEED_IP(2, 0); } next = get_unaligned_le16(ip); ip += 2; @@ -154,7 +174,7 @@ copy_literal_run: #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) if (op - m_pos >= 8) { unsigned char *oe = op + t; - if (likely(HAVE_OP(t + 15))) { + if (likely(HAVE_OP(t, 15))) { do { COPY8(op, m_pos); op += 8; @@ -164,7 +184,7 @@ copy_literal_run: m_pos += 8; } while (op < oe); op = oe; - if (HAVE_IP(6)) { + if (HAVE_IP(6, 0)) { state = next; COPY4(op, ip); op += next; @@ -172,7 +192,7 @@ copy_literal_run: continue; } } else { - NEED_OP(t); + NEED_OP(t, 0); do { *op++ = *m_pos++; } while (op < oe); @@ -181,7 +201,7 @@ copy_literal_run: #endif { unsigned char *oe = op + t; - NEED_OP(t); + NEED_OP(t, 0); op[0] = m_pos[0]; op[1] = m_pos[1]; op += 2; @@ -194,15 +214,15 @@ match_next: state = next; t = next; #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) - if (likely(HAVE_IP(6) && HAVE_OP(4))) { + if (likely(HAVE_IP(6, 0) && HAVE_OP(4, 0))) { COPY4(op, ip); op += t; ip += t; } else #endif { - NEED_IP(t + 3); - NEED_OP(t); + NEED_IP(t, 3); + NEED_OP(t, 0); while (t > 0) { *op++ = *ip++; t--; -- cgit v0.10.2 From 206204a1162b995e2185275167b22468c00d6b36 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Fri, 20 Jun 2014 22:01:41 -0700 Subject: lz4: ensure length does not wrap Given some pathologically compressed data, lz4 could possibly decide to wrap a few internal variables, causing unknown things to happen. Catch this before the wrapping happens and abort the decompression. Reported-by: "Don A. Bailey" Cc: stable Signed-off-by: Greg Kroah-Hartman diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c index df6839e..99a03ac 100644 --- a/lib/lz4/lz4_decompress.c +++ b/lib/lz4/lz4_decompress.c @@ -72,6 +72,8 @@ static int lz4_uncompress(const char *source, char *dest, int osize) len = *ip++; for (; len == 255; length += 255) len = *ip++; + if (unlikely(length > (size_t)(length + len))) + goto _output_error; length += len; } -- cgit v0.10.2