summaryrefslogtreecommitdiff
path: root/usr.bin/compress
diff options
context:
space:
mode:
authorjoerg <joerg@NetBSD.org>2011-08-16 13:55:01 +0000
committerjoerg <joerg@NetBSD.org>2011-08-16 13:55:01 +0000
commit0537e598eba537816c6486bde3d57504b0032051 (patch)
treea246b5fa02b41e5e75dafd2b87f1c0a36500280e /usr.bin/compress
parent0b9467010b26738c504fba3b1244c10ea9055ff9 (diff)
Do proper input validation without penalizing performance.
Diffstat (limited to 'usr.bin/compress')
-rw-r--r--usr.bin/compress/zopen.c40
1 files changed, 20 insertions, 20 deletions
diff --git a/usr.bin/compress/zopen.c b/usr.bin/compress/zopen.c
index 68d41dc3c2a..0d3f178d164 100644
--- a/usr.bin/compress/zopen.c
+++ b/usr.bin/compress/zopen.c
@@ -1,4 +1,4 @@
-/* $NetBSD: zopen.c,v 1.14 2011/08/16 03:24:47 christos Exp $ */
+/* $NetBSD: zopen.c,v 1.15 2011/08/16 13:55:01 joerg Exp $ */
/*-
* Copyright (c) 1985, 1986, 1992, 1993
@@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)zopen.c 8.1 (Berkeley) 6/27/93";
#else
-static char rcsid[] = "$NetBSD: zopen.c,v 1.14 2011/08/16 03:24:47 christos Exp $";
+static char rcsid[] = "$NetBSD: zopen.c,v 1.15 2011/08/16 13:55:01 joerg Exp $";
#endif
#endif /* LIBC_SCCS and not lint */
@@ -486,7 +486,7 @@ zread(void *cookie, char *rbp, int num)
block_compress = maxbits & BLOCK_MASK;
maxbits &= BIT_MASK;
maxmaxcode = 1L << maxbits;
- if (maxbits > BITS) {
+ if (maxbits > BITS || maxbits < 12) {
errno = EFTYPE;
return (-1);
}
@@ -497,14 +497,7 @@ zread(void *cookie, char *rbp, int num)
tab_suffixof(code) = (char_type) code;
}
free_ent = block_compress ? FIRST : 256;
-
- finchar = oldcode = getcode(zs);
- if (oldcode == -1) /* EOF already? */
- return (0); /* Get out of here */
-
- /* First code must be 8 bits = char. */
- *bp++ = (u_char)finchar;
- count--;
+ oldcode = -1;
stackp = de_stack;
while ((code = getcode(zs)) > -1) {
@@ -513,24 +506,31 @@ zread(void *cookie, char *rbp, int num)
for (code = 255; code >= 0; code--)
tab_prefixof(code) = 0;
clear_flg = 1;
- free_ent = FIRST - 1;
- if ((code = getcode(zs)) == -1) /* O, untimely death! */
- break;
+ free_ent = FIRST;
+ oldcode = -1;
+ continue;
}
incode = code;
- /* Special case FOR kWkWk string. */
+ /* Special case for kWkWk string. */
if (code >= free_ent) {
+ if (code > free_ent || oldcode == -1) {
+ /* Bad stream. */
+ errno = EINVAL;
+ return (-1);
+ }
*stackp++ = finchar;
code = oldcode;
}
+ /*
+ * The above condition ensures that code < free_ent.
+ * The construction of tab_prefixof in turn guarantees that
+ * each iteration decreases code and therefore stack usage is
+ * bound by 1 << BITS - 256.
+ */
/* Generate output characters in reverse order. */
while (code >= 256) {
- if (stackp - de_stack >= HSIZE - 1) {
- errno = EOVERFLOW;
- return -1;
- }
*stackp++ = tab_suffixof(code);
code = tab_prefixof(code);
}
@@ -544,7 +544,7 @@ middle: do {
} while (stackp > de_stack);
/* Generate the new entry. */
- if ((code = free_ent) < maxmaxcode) {
+ if ((code = free_ent) < maxmaxcode && oldcode != -1) {
tab_prefixof(code) = (u_short) oldcode;
tab_suffixof(code) = finchar;
free_ent = code + 1;