[klibc] [klibc:master] inet: Stricter byte parsing in inet_aton()
klibc-bot for Ben Hutchings
ben at decadent.org.uk
Thu Mar 21 15:36:13 PDT 2024
Commit-ID: d539458148cb998600b4596227cd52eb1ca930da
Gitweb: http://git.kernel.org/?p=libs/klibc/klibc.git;a=commit;h=d539458148cb998600b4596227cd52eb1ca930da
Author: Ben Hutchings <ben at decadent.org.uk>
AuthorDate: Thu, 21 Mar 2024 23:08:22 +0100
Committer: Ben Hutchings <ben at decadent.org.uk>
CommitDate: Thu, 21 Mar 2024 23:28:39 +0100
[klibc] inet: Stricter byte parsing in inet_aton()
sscanf() skips spaces in some places, and accepts values that are
out-of-range for a byte, so the following strings are wrongly
accepted:
"1.2.3.256"
"256.1.2.3"
"-1.2.3.4"
"1.2.3.-4"
" 1.2.3.4"
"1. 2.3.4"
"1.2.3.4 "
"1.2.3.0x4"
Implement our own strict conversion of decimal digits to bytes.
Signed-off-by: Ben Hutchings <ben at decadent.org.uk>
---
usr/klibc/inet/inet_aton.c | 30 ++++++++++++++++++++++++------
1 file changed, 24 insertions(+), 6 deletions(-)
diff --git a/usr/klibc/inet/inet_aton.c b/usr/klibc/inet/inet_aton.c
index beceeea3..954e5d8d 100644
--- a/usr/klibc/inet/inet_aton.c
+++ b/usr/klibc/inet/inet_aton.c
@@ -3,20 +3,38 @@
*/
#include <arpa/inet.h>
+#include <ctype.h>
#include <stdio.h>
int inet_aton(const char *str, struct in_addr *addr)
{
+ int i = 0, digits = 0, val = 0;
union {
uint8_t b[4];
uint32_t l;
} a;
+ char ch;
- if (sscanf(str, "%hhu.%hhu.%hhu.%hhu",
- &a.b[0], &a.b[1], &a.b[2], &a.b[3]) == 4) {
- addr->s_addr = a.l; /* Always in network byte order */
- return 1;
- } else {
- return 0;
+ for (;;) {
+ ch = *str++;
+ if (ch == (i == 3 ? 0 : '.')) {
+ if (digits == 0)
+ return 0;
+ a.b[i] = val;
+ if (++i == 4)
+ break;
+ digits = 0;
+ val = 0;
+ } else if (isdigit((unsigned char)ch)) {
+ digits++;
+ val = val * 10 + (ch - '0');
+ if (val > 0xff)
+ return 0;
+ } else {
+ return 0;
+ }
}
+
+ addr->s_addr = a.l;
+ return 1;
}
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