Fix buffer overflow in config parser

When interpreting a config value, the config parser reads in 1+ space
character(s) and puts -one- space character in the buffer as soon as
the first non-space character is encountered (if not inside quotes).

Unfortunately the buffer size check lacks the extra space character
which gets inserted at the next non-space character, resulting in
a crash with a specially crafted config entry.

The unit test now uses Java to compile a platform independent
.NET framework to output the test string in C# :o)

    Read: Thanks to Johannes Sixt for the correct printf call
    which replaces the perl invocation.

Signed-off-by: Thomas Jarosch <thomas.jarosch@intra2net.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/config.c b/config.c
index 82807c83b20ef8fbabfda7d476feff92f2dbb823..b9b2ce82378408cfd7d72245eff44efb7a8e1ec8 100644 (file)
--- a/config.c
+++ b/config.c
@@ -51,7 +51,7 @@ static char *parse_value(void)
 
        for (;;) {
                int c = get_next_char();
-               if (len >= sizeof(value))
+               if (len >= sizeof(value) - 1)
                        return NULL;
                if (c == '\n') {
                        if (quote)

diff --git a/t/t1303-wacky-config.sh b/t/t1303-wacky-config.sh
index 1983076c753ea12a4f69d2a98eda3c1621daed59..080117c6bcbb61078539f36011ecd62780bae305 100755 (executable)
--- a/t/t1303-wacky-config.sh
+++ b/t/t1303-wacky-config.sh
@@ -10,7 +10,7 @@ setup() {
 
 check() {
        echo "$2" >expected
-       git config --get "$1" >actual
+       git config --get "$1" >actual 2>&1
        test_cmp actual expected
 }
 
@@ -40,4 +40,11 @@ test_expect_success 'make sure git config escapes section names properly' '
        check "$SECTION" bar
 '
 
+LONG_VALUE=$(printf "x%01021dx a" 7)
+test_expect_success 'do not crash on special long config line' '
+       setup &&
+       git config section.key "$LONG_VALUE" &&
+       check section.key "fatal: bad config file line 2 in .git/config"
+'
+
 test_done