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path: root/util/libreboot-utils/lib/string.c
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Diffstat (limited to 'util/libreboot-utils/lib/string.c')
-rw-r--r--util/libreboot-utils/lib/string.c135
1 files changed, 89 insertions, 46 deletions
diff --git a/util/libreboot-utils/lib/string.c b/util/libreboot-utils/lib/string.c
index f56a4e55..7f336eb6 100644
--- a/util/libreboot-utils/lib/string.c
+++ b/util/libreboot-utils/lib/string.c
@@ -24,17 +24,25 @@
*/
#define ff ((size_t)-1 / 0xFF)
#define high ((ff) * 0x80)
+/* NOTE:
+ * do not assume that a match means
+ * both words have null at the same
+ * location. see how this is handled
+ * e.g. in scmp.
+ */
#define zeroes(x) (((x) - (ff)) & ~(x) & (high))
size_t
page_remain(const void *p)
{
+ /* calling sysconf repeatedly
+ * is folly. cache it (static)
+ */
static size_t pagesz = 0;
if (!pagesz)
- pagesz = pagesize(),
- pagesz -= ((uintptr_t)p & (pagesz - 1));
+ pagesz = (size_t)pagesize();
- return pagesz;
+ return pagesz - ((uintptr_t)p & (pagesz - 1));
}
long
@@ -122,49 +130,56 @@ scmp(const char *a,
size_t j;
size_t wa;
size_t wb;
+ int saved_errno = errno;
- if (a == NULL ||
- b == NULL ||
- rval == NULL) {
- errno = EFAULT;
+ if (if_err(a == NULL || b == NULL || rval == NULL, EFAULT))
goto err;
- }
for ( ; ((uintptr_t)(a + i) % sizeof(size_t)) != 0; i++) {
- if (i >= maxlen)
+ if (if_err(i >= maxlen, EOVERFLOW))
goto err;
else if (!ccmp(a, b, i, rval))
- return 0;
+ goto out;
}
for ( ; i + sizeof(size_t) <= maxlen;
i += sizeof(size_t)) {
+ /* prevent crossing page boundary on word check */
+ if (page_remain(a + i) < sizeof(size_t) ||
+ page_remain(b + i) < sizeof(size_t))
+ break;
+
memcpy(&wa, a + i, sizeof(size_t));
memcpy(&wb, b + i, sizeof(size_t));
if (wa != wb)
for (j = 0; j < sizeof(size_t); j++)
if (!ccmp(a, b, i + j, rval))
- return 0;
+ goto out;
if (!zeroes(wa))
continue;
*rval = 0;
- return 0;
+ goto out;
}
for ( ; i < maxlen; i++)
if (!ccmp(a, b, i, rval))
- return 0;
+ goto out;
err:
- errno = EFAULT;
+ (void) set_errno(saved_errno, EFAULT);
if (rval != NULL)
*rval = -1;
+
+ err_exit(errno, "scmp");
return -1;
+out:
+ errno = saved_errno;
+ return 0;
}
int ccmp(const char *a, const char *b,
@@ -173,9 +188,8 @@ int ccmp(const char *a, const char *b,
unsigned char ac;
unsigned char bc;
- if (if_err(a == NULL || b == NULL, EFAULT) ||
- rval == NULL)
- return -1;
+ if (if_err(a == NULL || b == NULL || rval == NULL, EFAULT))
+ err_exit(errno, "ccmp");
ac = (unsigned char)a[i];
bc = (unsigned char)b[i];
@@ -197,15 +211,13 @@ slen(const char *s,
size_t maxlen,
size_t *rval)
{
+ int saved_errno = errno;
size_t i = 0;
size_t w;
size_t j;
- if (s == NULL ||
- rval == NULL) {
- errno = EFAULT;
+ if (if_err(s == NULL || rval == NULL, EFAULT))
goto err;
- }
for ( ; ((uintptr_t)(s + i) % sizeof(size_t)) != 0; i++) {
@@ -213,7 +225,7 @@ slen(const char *s,
goto err;
if (s[i] == '\0') {
*rval = i;
- return 0;
+ goto out;
}
}
@@ -221,14 +233,13 @@ slen(const char *s,
i += sizeof(size_t)) {
memcpy(&w, s + i, sizeof(size_t));
-
if (!zeroes(w))
continue;
for (j = 0; j < sizeof(size_t); j++) {
if (s[i + j] == '\0') {
*rval = i + j;
- return 0;
+ goto out;
}
}
}
@@ -236,15 +247,20 @@ slen(const char *s,
for ( ; i < maxlen; i++) {
if (s[i] == '\0') {
*rval = i;
- return 0;
+ goto out;
}
}
err:
- errno = EFAULT;
+ (void) set_errno(saved_errno, EFAULT);
if (rval != NULL)
*rval = 0;
+
+ err_exit(errno, "slen");
return -1;
+out:
+ errno = saved_errno;
+ return 0;
}
/* strict word-based strdup */
@@ -256,21 +272,22 @@ sdup(const char *s,
size_t w;
size_t i = 0;
char *out = NULL;
+ int saved_errno = errno;
- if (dest == NULL || *dest != NULL || s == NULL)
+ if (if_err(dest == NULL || *dest != NULL || s == NULL, EFAULT))
goto err;
out = smalloc(dest, max);
for ( ; ((uintptr_t)(s + i) % sizeof(size_t)) != 0; i++) {
- if (i >= max)
+ if (if_err(i >= max, EOVERFLOW))
goto err;
out[i] = s[i];
if (s[i] == '\0') {
*dest = out;
- return 0;
+ goto out;
}
}
@@ -290,7 +307,7 @@ sdup(const char *s,
out[i + j] = s[i + j];
if (s[i + j] == '\0') {
*dest = out;
- return 0;
+ goto out;
}
}
}
@@ -300,7 +317,7 @@ sdup(const char *s,
out[i] = s[i];
if (s[i] == '\0') {
*dest = out;
- return 0;
+ goto out;
}
}
@@ -308,8 +325,14 @@ err:
free_and_set_null(&out);
if (dest != NULL)
*dest = NULL;
- errno = EFAULT;
+
+ (void) set_errno(saved_errno, EFAULT);
+ err_exit(errno, "sdup");
+
return -1;
+out:
+ errno = saved_errno;
+ return 0;
}
/* concatenate N number of strings */
@@ -347,6 +370,7 @@ scatn(ssize_t sc, const char **sv,
rtmp = NULL;
}
+ errno = saved_errno;
*rval = final;
return 0;
err:
@@ -354,7 +378,10 @@ err:
free_and_set_null(&rtmp);
free_and_set_null(&final);
- return set_errno(saved_errno, EFAULT);
+ (void) set_errno(saved_errno, EFAULT);
+
+ err_exit(errno, "scatn");
+ return -1;
}
/* strict strcat */
@@ -365,16 +392,16 @@ scat(const char *s1, const char *s2,
size_t size1;
size_t size2;
char *rval = NULL;
+ int saved_errno = errno;
- if (if_err(dest == NULL || *dest != NULL, EFAULT) ||
- slen(s1, n, &size1) < 0 ||
- slen(s2, n, &size2) < 0 ||
- if_err(size1 > SIZE_MAX - size2 - 1, EOVERFLOW)) {
+ if (if_err(dest == NULL || *dest != NULL, EFAULT))
+ goto err;
- if (dest != NULL)
- *dest = NULL;
- return -1;
- }
+ slen(s1, n, &size1);
+ slen(s2, n, &size2);
+
+ if (if_err(size1 > SIZE_MAX - size2 - 1, EOVERFLOW))
+ goto err;
memcpy(smalloc(&rval, size1 + size2 + 1),
s1, size1);
@@ -382,7 +409,15 @@ scat(const char *s1, const char *s2,
*(rval + size1 + size2) = '\0';
*dest = rval;
+ errno = saved_errno;
return 0;
+err:
+ (void) set_errno(saved_errno, EINVAL);
+ if (dest != NULL)
+ *dest = NULL;
+ err_exit(errno, "scat");
+
+ return -1;
}
/* strict split/de-cat - off is where
@@ -395,14 +430,16 @@ dcat(const char *s, size_t n,
size_t size;
char *rval1 = NULL;
char *rval2 = NULL;
+ int saved_errno = errno;
+
+ if (if_err(dest1 == NULL || dest2 == NULL, EFAULT))
+ goto err;
- if (dest1 == NULL || dest2 == NULL ||
- slen(s, n, &size) < 0 ||
- if_err(size == SIZE_MAX, EOVERFLOW) ||
- if_err(off >= size, EOVERFLOW)) {
+ slen(s, n, &size);
+ if (if_err(size >= SIZE_MAX - 1, EOVERFLOW) ||
+ if_err(off >= size, EOVERFLOW))
goto err;
- }
memcpy(smalloc(&rval1, off + 1),
s, off);
@@ -415,6 +452,7 @@ dcat(const char *s, size_t n,
*dest1 = rval1;
*dest2 = rval2;
+ errno = saved_errno;
return 0;
err:
@@ -423,6 +461,9 @@ err:
free_and_set_null(&rval1);
free_and_set_null(&rval2);
+ (void) set_errno(saved_errno, EINVAL);
+ err_exit(errno, "dcat");
+
return -1;
}
@@ -433,6 +474,7 @@ err:
int
vcmp(const void *s1, const void *s2, size_t n)
{
+ int saved_errno = errno;
size_t i = 0;
size_t a;
size_t b;
@@ -459,6 +501,7 @@ vcmp(const void *s1, const void *s2, size_t n)
if (x[i] != y[i])
return (int)x[i] - (int)y[i];
+ errno = saved_errno;
return 0;
}
generated by cgit v1.2.1 (git 2.18.0) at 2026-03-30 21:01:13 +0000