summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDenys Vlasenko <vda.linux@googlemail.com>2011-08-09 02:05:13 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2011-08-09 02:05:13 (GMT)
commit7485086f1eca78998d6cd31b0ce18a8a8ea3fc35 (patch)
treead3a754a07e29b0c86514bdac98c63618628b37d
parent6e42b89b8d136316e1b97b56cf885e8ef9d64caf (diff)
downloadbusybox-7485086f1eca78998d6cd31b0ce18a8a8ea3fc35.tar.gz
busybox-7485086f1eca78998d6cd31b0ce18a8a8ea3fc35.tar.bz2
die_if_bad_username: tighten up a bit
function old new delta die_if_bad_username 77 97 +20 Based on patches from Tito. The changes are: better comments we disallow '@' now - in practice such usernames will be unusable use of the portable filename character set plus '$' don't use isalnum as it allows non-ASCII letters in legacy 8-bit locales (pointed out by Rich Felker) enforce maximum length of LOGIN_NAME_MAX (including NUL) don't allow '$', '.', and '-' as first char don't print the illegal char in error message as if it is a wide char it will be unreadable print the position of the illegal character Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--libbb/die_if_bad_username.c42
1 files changed, 32 insertions, 10 deletions
diff --git a/libbb/die_if_bad_username.c b/libbb/die_if_bad_username.c
index 9946e3a..cf1297b 100644
--- a/libbb/die_if_bad_username.c
+++ b/libbb/die_if_bad_username.c
@@ -18,23 +18,45 @@
void FAST_FUNC die_if_bad_username(const char *name)
{
- /* 1st char being dash or dot isn't valid: */
- goto skip;
- /* For example, name like ".." can make adduser
- * chown "/home/.." recursively - NOT GOOD
+ const char *start = name;
+
+ /* 1st char being dash or dot isn't valid:
+ * for example, name like ".." can make adduser
+ * chown "/home/.." recursively - NOT GOOD.
+ * Name of just a single "$" is also rejected.
*/
+ goto skip;
do {
- if (*name == '-' || *name == '.')
+ unsigned char ch;
+
+ /* These chars are valid unless they are at the 1st pos: */
+ if (*name == '-'
+ || *name == '.'
+ /* $ is allowed if it's the last char: */
+ || (*name == '$' && !name[1])
+ ) {
continue;
+ }
skip:
- if (isalnum(*name)
- || *name == '_'
- || *name == '@'
- || (*name == '$' && !name[1])
+ ch = *name;
+ if (ch == '_'
+ /* || ch == '@' -- we disallow this too. Think about "user@host" */
+ /* open-coded isalnum: */
+ || (ch >= '0' && ch <= '9')
+ || ((ch|0x20) >= 'a' && (ch|0x20) <= 'z')
) {
continue;
}
- bb_error_msg_and_die("illegal character '%c'", *name);
+ bb_error_msg_and_die("illegal character with code %u at position %u",
+ (unsigned)ch, (unsigned)(name - start));
} while (*++name);
+
+ /* The minimum size of the login name is one char or two if
+ * last char is the '$'. Violations of this are caught above.
+ * The maximum size of the login name is LOGIN_NAME_MAX
+ * including the terminating null byte.
+ */
+ if (name - start >= LOGIN_NAME_MAX)
+ bb_error_msg_and_die("name is too long");
}