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unzip: test for bad archive SEGVing

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function                                             old     new   delta
huft_build                                          1296    1300      +4

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko
2015-10-26 19:33:05 +01:00
parent d683c5c2f1
commit 1de25a6e87
2 changed files with 29 additions and 5 deletions
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11
archival/libarchive/decompress_gunzip.c
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@@ -305,11 +305,12 @@ static int huft_build(const unsigned *b, const unsigned n,
unsigned i; /* counter, current code */
unsigned j; /* counter */
int k; /* number of bits in current code */
unsigned *p; /* pointer into c[], b[], or v[] */
const unsigned *p; /* pointer into c[], b[], or v[] */
huft_t *q; /* points to current table */
huft_t r; /* table entry for structure assignment */
huft_t *u[BMAX]; /* table stack */
unsigned v[N_MAX]; /* values in order of bit length */
unsigned v_end;
int ws[BMAX + 1]; /* bits decoded stack */
int w; /* bits decoded */
unsigned x[BMAX + 1]; /* bit offsets, then code stack */
@@ -324,7 +325,7 @@ static int huft_build(const unsigned *b, const unsigned n,
/* Generate counts for each bit length */
memset(c, 0, sizeof(c));
p = (unsigned *) b; /* cast allows us to reuse p for pointing to b */
p = b;
i = n;
do {
c[*p]++; /* assume all entries <= BMAX */
@@ -365,12 +366,14 @@ static int huft_build(const unsigned *b, const unsigned n,
}
/* Make a table of values in order of bit lengths */
p = (unsigned *) b;
p = b;
i = 0;
v_end = 0;
do {
j = *p++;
if (j != 0) {
v[x[j]++] = i;
v_end = x[j];
}
} while (++i < n);
@@ -432,7 +435,7 @@ static int huft_build(const unsigned *b, const unsigned n,
/* set up table entry in r */
r.b = (unsigned char) (k - w);
if (p >= v + n) {
if (p >= v + v_end) { // Was "if (p >= v + n)" but v[] can be shorter!
r.e = 99; /* out of values--invalid code */
} else if (*p < s) {
r.e = (unsigned char) (*p < 256 ? 16 : 15); /* 256 is EOB code */