From 912b213927c79feb8254549b13eba41870d56081 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 commit 206a81c18401c0cde6e579164f752c4b147324ce upstream. 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. Change-Id: I13c97fd70481d4d272beb8ba495a8be3c4b48cf2 Reported-by: "Don A. Bailey" Tested-by: "Don A. Bailey" Signed-off-by: Greg Kroah-Hartman --- lib/lzo/lzo1x_decompress_safe.c | 62 +++++++++++++++++++++++++++-------------- 1 file changed, 41 insertions(+), 21 deletions(-) (limited to 'lib') diff --git a/lib/lzo/lzo1x_decompress_safe.c b/lib/lzo/lzo1x_decompress_safe.c index e3edc5f..a5f3d0e 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 { @@ -83,8 +103,8 @@ 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); @@ -97,7 +117,7 @@ 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; @@ -121,10 +141,10 @@ 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); @@ -139,10 +159,10 @@ 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; @@ -156,7 +176,7 @@ 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; @@ -168,7 +188,7 @@ copy_literal_run: # endif } while (op < oe); op = oe; - if (HAVE_IP(6)) { + if (HAVE_IP(6, 0)) { state = next; COPY4(op, ip); op += next; @@ -176,7 +196,7 @@ copy_literal_run: continue; } } else { - NEED_OP(t); + NEED_OP(t, 0); do { *op++ = *m_pos++; } while (op < oe); @@ -185,7 +205,7 @@ 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; @@ -198,15 +218,15 @@ 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 v1.1