path: root/sideband.c
diff options
authorJunio C Hamano <>2018-08-18 16:16:28 (GMT)
committerJunio C Hamano <>2018-08-18 16:16:48 (GMT)
commit59a255aef05633c45c780987fa0c861cda9006f2 (patch)
treeb47a7434e8bb1bdd483014cef6fdf1bbc654dafc /sideband.c
parentbf1a11f0a100b080a25233980c14b5ae8f3a7d2d (diff)
sideband: do not read beyond the end of input
The caller of maybe_colorize_sideband() gives a counted buffer <src, n>, but the callee checked src[] as if it were a NUL terminated buffer. If src[] had all isspace() bytes in it, we would have made n negative, and then (1) made number of strncasecmp() calls to see if the remaining bytes in src[] matched keywords, reading beyond the end of the array (this actually happens even if n does not go negative), and/or (2) called strbuf_add() with negative count, most likely triggering the "you want to use way too much memory" error due to unsigned integer overflow. Fix both issues by making sure we do not go beyond &src[n]. In the longer term we may want to accept size_t as parameter for clarity (even though we know that a sideband message we are painting typically would fit on a line on a terminal and int is sufficient). Write it down as a NEEDSWORK comment. Helped-by: Jonathan Nieder <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'sideband.c')
1 files changed, 6 insertions, 2 deletions
diff --git a/sideband.c b/sideband.c
index 1c6bb0e..368647a 100644
--- a/sideband.c
+++ b/sideband.c
@@ -65,6 +65,8 @@ void list_config_color_sideband_slots(struct string_list *list, const char *pref
* Optionally highlight one keyword in remote output if it appears at the start
* of the line. This should be called for a single line only, which is
* passed as the first N characters of the SRC array.
+ *
+ * NEEDSWORK: use "size_t n" instead for clarity.
static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
@@ -75,7 +77,7 @@ static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
- while (isspace(*src)) {
+ while (0 < n && isspace(*src)) {
strbuf_addch(dest, *src);
@@ -84,6 +86,9 @@ static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
for (i = 0; i < ARRAY_SIZE(keywords); i++) {
struct keyword_entry *p = keywords + i;
int len = strlen(p->keyword);
+ if (n <= len)
+ continue;
* Match case insensitively, so we colorize output from existing
* servers regardless of the case that they use for their
@@ -101,7 +106,6 @@ static void maybe_colorize_sideband(struct strbuf *dest, const char *src, int n)
strbuf_add(dest, src, n);