diff options
Diffstat (limited to 'decompress.c')
| -rw-r--r-- | decompress.c | 34 |
1 files changed, 30 insertions, 4 deletions
diff --git a/decompress.c b/decompress.c index bba5e0f..a1a0bac 100644 --- a/decompress.c +++ b/decompress.c @@ -8,8 +8,8 @@ This file is part of bzip2/libbzip2, a program and library for lossless, block-sorting data compression. - bzip2/libbzip2 version 1.0.5 of 10 December 2007 - Copyright (C) 1996-2007 Julian Seward <jseward@bzip.org> + bzip2/libbzip2 version 1.0.8 of 13 July 2019 + Copyright (C) 1996-2019 Julian Seward <jseward@acm.org> Please read the WARNING, DISCLAIMER and PATENTS sections in the README file. @@ -285,7 +285,7 @@ Int32 BZ2_decompress ( DState* s ) /*--- Now the selectors ---*/ GET_BITS(BZ_X_SELECTOR_1, nGroups, 3); - if (nGroups < 2 || nGroups > 6) RETURN(BZ_DATA_ERROR); + if (nGroups < 2 || nGroups > BZ_N_GROUPS) RETURN(BZ_DATA_ERROR); GET_BITS(BZ_X_SELECTOR_2, nSelectors, 15); if (nSelectors < 1) RETURN(BZ_DATA_ERROR); for (i = 0; i < nSelectors; i++) { @@ -296,8 +296,14 @@ Int32 BZ2_decompress ( DState* s ) j++; if (j >= nGroups) RETURN(BZ_DATA_ERROR); } - s->selectorMtf[i] = j; + /* Having more than BZ_MAX_SELECTORS doesn't make much sense + since they will never be used, but some implementations might + "round up" the number of selectors, so just ignore those. */ + if (i < BZ_MAX_SELECTORS) + s->selectorMtf[i] = j; } + if (nSelectors > BZ_MAX_SELECTORS) + nSelectors = BZ_MAX_SELECTORS; /*--- Undo the MTF values for the selectors. ---*/ { @@ -381,6 +387,13 @@ Int32 BZ2_decompress ( DState* s ) es = -1; N = 1; do { + /* Check that N doesn't get too big, so that es doesn't + go negative. The maximum value that can be + RUNA/RUNB encoded is equal to the block size (post + the initial RLE), viz, 900k, so bounding N at 2 + million should guard against overflow without + rejecting any legitimate inputs. */ + if (N >= 2*1024*1024) RETURN(BZ_DATA_ERROR); if (nextSym == BZ_RUNA) es = es + (0+1) * N; else if (nextSym == BZ_RUNB) es = es + (1+1) * N; N = N * 2; @@ -485,15 +498,28 @@ Int32 BZ2_decompress ( DState* s ) RETURN(BZ_DATA_ERROR); /*-- Set up cftab to facilitate generation of T^(-1) --*/ + /* Check: unzftab entries in range. */ + for (i = 0; i <= 255; i++) { + if (s->unzftab[i] < 0 || s->unzftab[i] > nblock) + RETURN(BZ_DATA_ERROR); + } + /* Actually generate cftab. */ s->cftab[0] = 0; for (i = 1; i <= 256; i++) s->cftab[i] = s->unzftab[i-1]; for (i = 1; i <= 256; i++) s->cftab[i] += s->cftab[i-1]; + /* Check: cftab entries in range. */ for (i = 0; i <= 256; i++) { if (s->cftab[i] < 0 || s->cftab[i] > nblock) { /* s->cftab[i] can legitimately be == nblock */ RETURN(BZ_DATA_ERROR); } } + /* Check: cftab entries non-descending. */ + for (i = 1; i <= 256; i++) { + if (s->cftab[i-1] > s->cftab[i]) { + RETURN(BZ_DATA_ERROR); + } + } s->state_out_len = 0; s->state_out_ch = 0; |