[g]unzip: fix recent breakage.

Also, do emit error message we so painstakingly pass from gzip internals

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

2 files changed, 22 insertions, 12 deletions

diff --git a/archival/libarchive/decompress_gunzip.c b/archival/libarchive/decompress_gunzip.c
index 30bf45154..20e4d9ac5 100644
--- a/archival/libarchive/decompress_gunzip.c
+++ b/archival/libarchive/decompress_gunzip.c
@@ -309,8 +309,7 @@ static int huft_build(const unsigned *b, const unsigned n,
         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;
+        unsigned v[N_MAX + 1];  /* values in order of bit length. last v[] is never used */
         int ws[BMAX + 1];       /* bits decoded stack */
         int w;                  /* bits decoded */
         unsigned x[BMAX + 1];   /* bit offsets, then code stack */
@@ -365,15 +364,17 @@ static int huft_build(const unsigned *b, const unsigned n,
                 *xp++ = j;
         }
 
-        /* Make a table of values in order of bit lengths */
+        /* Make a table of values in order of bit lengths.
+         * To detect bad input, unused v[i]'s are set to invalid value UINT_MAX.
+         * In particular, last v[i] is never filled and must not be accessed.
+         */
+        memset(v, 0xff, sizeof(v));
         p = b;
         i = 0;
-        v_end = 0;
         do {
                 j = *p++;
                 if (j != 0) {
                         v[x[j]++] = i;
-                        v_end = x[j];
                 }
         } while (++i < n);
 
@@ -435,7 +436,9 @@ 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 + v_end) { // Was "if (p >= v + n)" but v[] can be shorter!
+                        if (/*p >= v + n || -- redundant, caught by the second check: */
+                            *p == UINT_MAX /* do we access uninited v[i]? (see memset(v))*/
+                        ) {
                                 r.e = 99; /* out of values--invalid code */
                         } else if (*p < s) {
                                 r.e = (unsigned char) (*p < 256 ? 16 : 15);     /* 256 is EOB code */
@@ -520,8 +523,9 @@ static NOINLINE int inflate_codes(STATE_PARAM_ONLY)
                 e = t->e;
                 if (e > 16)
                         do {
-                                if (e == 99)
-                                        abort_unzip(PASS_STATE_ONLY);;
+                                if (e == 99) {
+                                        abort_unzip(PASS_STATE_ONLY);
+                                }
                                 bb >>= t->b;
                                 k -= t->b;
                                 e -= 16;
@@ -557,8 +561,9 @@ static NOINLINE int inflate_codes(STATE_PARAM_ONLY)
                         e = t->e;
                         if (e > 16)
                                 do {
-                                        if (e == 99)
+                                        if (e == 99) {
                                                 abort_unzip(PASS_STATE_ONLY);
+                                        }
                                         bb >>= t->b;
                                         k -= t->b;
                                         e -= 16;
@@ -824,8 +829,9 @@ static int inflate_block(STATE_PARAM smallint *e)
 
                 b_dynamic >>= 4;
                 k_dynamic -= 4;
-                if (nl > 286 || nd > 30)
+                if (nl > 286 || nd > 30) {
                         abort_unzip(PASS_STATE_ONLY);   /* bad lengths */
+                }
 
                 /* read in bit-length-code lengths */
                 for (j = 0; j < nb; j++) {
@@ -906,12 +912,14 @@ static int inflate_block(STATE_PARAM smallint *e)
                 bl = lbits;
 
                 i = huft_build(ll, nl, 257, cplens, cplext, &inflate_codes_tl, &bl);
-                if (i != 0)
+                if (i != 0) {
                         abort_unzip(PASS_STATE_ONLY);
+                }
                 bd = dbits;
                 i = huft_build(ll + nl, nd, 0, cpdist, cpdext, &inflate_codes_td, &bd);
-                if (i != 0)
+                if (i != 0) {
                         abort_unzip(PASS_STATE_ONLY);
+                }
 
                 /* set up data for inflate_codes() */
                 inflate_codes_setup(PASS_STATE bl, bd);
@@ -999,6 +1007,7 @@ inflate_unzip_internal(STATE_PARAM transformer_state_t *xstate)
         error_msg = "corrupted data";
         if (setjmp(error_jmp)) {
                 /* Error from deep inside zip machinery */
+                bb_error_msg(error_msg);
                 n = -1;
                 goto ret;
         }
diff --git a/testsuite/unzip.tests b/testsuite/unzip.tests
index ca0a45800..d8738a3bd 100755
--- a/testsuite/unzip.tests
+++ b/testsuite/unzip.tests
@@ -34,6 +34,7 @@ rm foo.zip
 testing "unzip (bad archive)" "uudecode; unzip bad.zip 2>&1; echo \$?" \
 "Archive:  bad.zip
   inflating: ]3j½r«IK-%Ix
+unzip: corrupted data
 unzip: inflate error
 1
 " \