svn commit: r366736 - head/usr.sbin/kldxref
Jessica Clarke
jrtc27 at FreeBSD.org
Thu Oct 15 18:03:14 UTC 2020
Author: jrtc27
Date: Thu Oct 15 18:03:14 2020
New Revision: 366736
URL: https://svnweb.freebsd.org/changeset/base/366736
Log:
kldxref: Avoid buffer overflows in parse_pnp_list
We convert a string like "W32:vendor/device" into "I:vendor;I:device",
where the output is longer than the input, but only allocate space equal
to the length of the input, leading to a buffer overflow.
Instead use open_memstream so we get a safe dynamically-grown buffer.
Found by: CHERI
Reviewed by: imp, jhb (mentor)
Approved by: imp, jhb (mentor)
Obtained from: CheriBSD
Differential Revision: https://reviews.freebsd.org/D26637
Modified:
head/usr.sbin/kldxref/kldxref.c
Modified: head/usr.sbin/kldxref/kldxref.c
==============================================================================
--- head/usr.sbin/kldxref/kldxref.c Thu Oct 15 17:44:17 2020 (r366735)
+++ head/usr.sbin/kldxref/kldxref.c Thu Oct 15 18:03:14 2020 (r366736)
@@ -235,14 +235,17 @@ parse_pnp_list(const char *desc, char **new_desc, pnp_
const char *walker, *ep;
const char *colon, *semi;
struct pnp_elt *elt;
- char *nd;
char type[8], key[32];
int off;
+ size_t new_desc_size;
+ FILE *fp;
walker = desc;
ep = desc + strlen(desc);
off = 0;
- nd = *new_desc = malloc(strlen(desc) + 1);
+ fp = open_memstream(new_desc, &new_desc_size);
+ if (fp == NULL)
+ err(1, "Could not open new memory stream");
if (verbose > 1)
printf("Converting %s into a list\n", desc);
while (walker < ep) {
@@ -336,42 +339,44 @@ parse_pnp_list(const char *desc, char **new_desc, pnp_
off = elt->pe_offset + sizeof(void *);
}
if (elt->pe_kind & TYPE_PAIRED) {
- char *word, *ctx;
+ char *word, *ctx, newtype;
for (word = strtok_r(key, "/", &ctx);
word; word = strtok_r(NULL, "/", &ctx)) {
- sprintf(nd, "%c:%s;", elt->pe_kind & TYPE_FLAGGED ? 'J' : 'I',
- word);
- nd += strlen(nd);
+ newtype = elt->pe_kind & TYPE_FLAGGED ? 'J' : 'I';
+ fprintf(fp, "%c:%s;", newtype, word);
}
-
}
else {
+ char newtype;
+
if (elt->pe_kind & TYPE_FLAGGED)
- *nd++ = 'J';
+ newtype = 'J';
else if (elt->pe_kind & TYPE_GE)
- *nd++ = 'G';
+ newtype = 'G';
else if (elt->pe_kind & TYPE_LE)
- *nd++ = 'L';
+ newtype = 'L';
else if (elt->pe_kind & TYPE_MASK)
- *nd++ = 'M';
+ newtype = 'M';
else if (elt->pe_kind & TYPE_INT)
- *nd++ = 'I';
+ newtype = 'I';
else if (elt->pe_kind == TYPE_D)
- *nd++ = 'D';
+ newtype = 'D';
else if (elt->pe_kind == TYPE_Z || elt->pe_kind == TYPE_E)
- *nd++ = 'Z';
+ newtype = 'Z';
else if (elt->pe_kind == TYPE_T)
- *nd++ = 'T';
+ newtype = 'T';
else
errx(1, "Impossible type %x\n", elt->pe_kind);
- *nd++ = ':';
- strcpy(nd, key);
- nd += strlen(nd);
- *nd++ = ';';
+ fprintf(fp, "%c:%s;", newtype, key);
}
}
- *nd++ = '\0';
+ if (ferror(fp) != 0) {
+ fclose(fp);
+ errx(1, "Exhausted space converting description %s", desc);
+ }
+ if (fclose(fp) != 0)
+ errx(1, "Failed to close memory stream");
return (0);
err:
errx(1, "Parse error of description string %s", desc);
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