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author | Lasse Collin <lasse.collin@tukaani.org> | 2011-11-11 14:33:30 +0100 |
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committer | Lasse Collin <lasse.collin@tukaani.org> | 2011-11-11 14:33:30 +0100 |
commit | 8e8ca04c7bbee50d35582d4f2748d644ebc47086 (patch) | |
tree | 2c2dd0cc72248dde79f4eef986ca210bda3dadee | |
parent | f4b38c6cd882bbc88c6a39a4f5d0fb81818fe107 (diff) | |
download | xen-8e8ca04c7bbee50d35582d4f2748d644ebc47086.tar.gz xen-8e8ca04c7bbee50d35582d4f2748d644ebc47086.tar.bz2 xen-8e8ca04c7bbee50d35582d4f2748d644ebc47086.zip |
Decompressors: check for write errors in unlzma.c
From: Lasse Collin <lasse.collin@tukaani.org>
The return value of wr->flush() is not checked in write_byte(). This
means that the decompressor won't stop even if the caller doesn't want
more data. This can happen e.g. with corrupt LZMA-compressed initramfs.
Returning the error quickly allows the user to see the error message
quicker.
There is a similar missing check for wr.flush() near the end of unlzma().
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
Committed-by: Jan Beulich <jbeulich@suse.com>
-rw-r--r-- | xen/common/unlzma.c | 53 |
1 files changed, 32 insertions, 21 deletions
diff --git a/xen/common/unlzma.c b/xen/common/unlzma.c index 781982b524..6dcd7ba20b 100644 --- a/xen/common/unlzma.c +++ b/xen/common/unlzma.c @@ -307,32 +307,38 @@ static inline uint8_t INIT peek_old_byte(struct writer *wr, } -static inline void INIT write_byte(struct writer *wr, uint8_t byte) +static inline int INIT write_byte(struct writer *wr, uint8_t byte) { wr->buffer[wr->buffer_pos++] = wr->previous_byte = byte; if (wr->flush && wr->buffer_pos == wr->header->dict_size) { wr->buffer_pos = 0; wr->global_pos += wr->header->dict_size; - wr->flush((char *)wr->buffer, wr->header->dict_size); + if (wr->flush((char *)wr->buffer, wr->header->dict_size) + != wr->header->dict_size) + return -1; } + return 0; } -static inline void INIT copy_byte(struct writer *wr, uint32_t offs) +static inline int INIT copy_byte(struct writer *wr, uint32_t offs) { - write_byte(wr, peek_old_byte(wr, offs)); + return write_byte(wr, peek_old_byte(wr, offs)); } -static inline void INIT copy_bytes(struct writer *wr, +static inline int INIT copy_bytes(struct writer *wr, uint32_t rep0, int len) { do { - copy_byte(wr, rep0); + if (copy_byte(wr, rep0)) + return -1; len--; } while (len != 0 && wr->buffer_pos < wr->header->dst_size); + + return len; } -static inline void INIT process_bit0(struct writer *wr, struct rc *rc, +static inline int INIT process_bit0(struct writer *wr, struct rc *rc, struct cstate *cst, uint16_t *p, int pos_state, uint16_t *prob, int lc, uint32_t literal_pos_mask) { @@ -366,16 +372,17 @@ static inline void INIT process_bit0(struct writer *wr, struct rc *rc, uint16_t *prob_lit = prob + mi; rc_get_bit(rc, prob_lit, &mi); } - write_byte(wr, mi); if (cst->state < 4) cst->state = 0; else if (cst->state < 10) cst->state -= 3; else cst->state -= 6; + + return write_byte(wr, mi); } -static inline void INIT process_bit1(struct writer *wr, struct rc *rc, +static inline int INIT process_bit1(struct writer *wr, struct rc *rc, struct cstate *cst, uint16_t *p, int pos_state, uint16_t *prob) { int offset; @@ -406,8 +413,7 @@ static inline void INIT process_bit1(struct writer *wr, struct rc *rc, cst->state = cst->state < LZMA_NUM_LIT_STATES ? 9 : 11; - copy_byte(wr, cst->rep0); - return; + return copy_byte(wr, cst->rep0); } else { rc_update_bit_1(rc, prob); } @@ -509,12 +515,12 @@ static inline void INIT process_bit1(struct writer *wr, struct rc *rc, } else cst->rep0 = pos_slot; if (++(cst->rep0) == 0) - return; + return 0; } len += LZMA_MATCH_MIN_LEN; - copy_bytes(wr, cst->rep0, len); + return copy_bytes(wr, cst->rep0, len); } @@ -617,11 +623,17 @@ STATIC int INIT unlzma(unsigned char *buf, unsigned int in_len, int pos_state = get_pos(&wr) & pos_state_mask; uint16_t *prob = p + LZMA_IS_MATCH + (cst.state << LZMA_NUM_POS_BITS_MAX) + pos_state; - if (rc_is_bit_0(&rc, prob)) - process_bit0(&wr, &rc, &cst, p, pos_state, prob, - lc, literal_pos_mask); - else { - process_bit1(&wr, &rc, &cst, p, pos_state, prob); + if (rc_is_bit_0(&rc, prob)) { + if (process_bit0(&wr, &rc, &cst, p, pos_state, prob, + lc, literal_pos_mask)) { + error("LZMA data is corrupt"); + goto exit_3; + } + } else { + if (process_bit1(&wr, &rc, &cst, p, pos_state, prob)) { + error("LZMA data is corrupt"); + goto exit_3; + } if (cst.rep0 == 0) break; } @@ -631,9 +643,8 @@ STATIC int INIT unlzma(unsigned char *buf, unsigned int in_len, if (posp) *posp = rc.ptr-rc.buffer; - if (wr.flush) - wr.flush(wr.buffer, wr.buffer_pos); - ret = 0; + if (!wr.flush || wr.flush(wr.buffer, wr.buffer_pos) == wr.buffer_pos) + ret = 0; exit_3: large_free(p); exit_2: |