libkmod: check strbuf return values

The strbuf functions may fail, so handle errors. Make especially sure
that push and pop operations stay in sync.

Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Link: https://github.com/kmod-project/kmod/pull/152
Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com>

diff --git a/libkmod/libkmod-index.c b/libkmod/libkmod-index.c
index 1c730ea4d2be435db7724e84e70b42a302b78205..1dec1edd4775988b0455ccc37768ac419d3bd323 100644 (file)
--- a/libkmod/libkmod-index.c
+++ b/libkmod/libkmod-index.c
@@ -289,6 +289,10 @@ static struct index_node_f *index_read(FILE *in, uint32_t offset)
                                goto err;
                        }
                        value = strbuf_str(&buf);
+                       if (value == NULL) {
+                               strbuf_release(&buf);
+                               goto err;
+                       }
                        add_value(&node->values, value, buf.used, priority);
                        strbuf_clear(&buf);
                }
@@ -391,9 +395,10 @@ static void index_dump_node(struct index_node_f *node, struct strbuf *buf, int f
                if (!child)
                        continue;
 
-               strbuf_pushchar(buf, ch);
-               index_dump_node(child, buf, fd);
-               strbuf_popchar(buf);
+               if (strbuf_pushchar(buf, ch)) {
+                       index_dump_node(child, buf, fd);
+                       strbuf_popchar(buf);
+               }
        }
 
        strbuf_popchars(buf, pushed);
@@ -410,8 +415,8 @@ void index_dump(struct index_file *in, int fd, const char *prefix)
                return;
 
        strbuf_init(&buf);
-       strbuf_pushchars(&buf, prefix);
-       index_dump_node(root, &buf, fd);
+       if (strbuf_pushchars(&buf, prefix))
+               index_dump_node(root, &buf, fd);
        strbuf_release(&buf);
 }
 
@@ -495,8 +500,7 @@ static void index_searchwild__all(struct index_node_f *node, int j, struct strbu
        while (node->prefix[j]) {
                ch = node->prefix[j];
 
-               strbuf_pushchar(buf, ch);
-               pushed++;
+               pushed += strbuf_pushchar(buf, ch);
                j++;
        }
 
@@ -506,13 +510,16 @@ static void index_searchwild__all(struct index_node_f *node, int j, struct strbu
                if (!child)
                        continue;
 
-               strbuf_pushchar(buf, ch);
-               index_searchwild__all(child, 0, buf, subkey, out);
-               strbuf_popchar(buf);
+               if (strbuf_pushchar(buf, ch)) {
+                       index_searchwild__all(child, 0, buf, subkey, out);
+                       strbuf_popchar(buf);
+               }
        }
 
        if (node->values) {
-               if (fnmatch(strbuf_str(buf), subkey, 0) == 0)
+               const char *s = strbuf_str(buf);
+
+               if (s != NULL && fnmatch(s, subkey, 0) == 0)
                        index_searchwild__allvalues(node, out);
                else
                        index_close(node);
@@ -550,23 +557,26 @@ static void index_searchwild__node(struct index_node_f *node, struct strbuf *buf
 
                child = index_readchild(node, '*');
                if (child) {
-                       strbuf_pushchar(buf, '*');
-                       index_searchwild__all(child, 0, buf, &key[i], out);
-                       strbuf_popchar(buf);
+                       if (strbuf_pushchar(buf, '*')) {
+                               index_searchwild__all(child, 0, buf, &key[i], out);
+                               strbuf_popchar(buf);
+                       }
                }
 
                child = index_readchild(node, '?');
                if (child) {
-                       strbuf_pushchar(buf, '?');
-                       index_searchwild__all(child, 0, buf, &key[i], out);
-                       strbuf_popchar(buf);
+                       if (strbuf_pushchar(buf, '?')) {
+                               index_searchwild__all(child, 0, buf, &key[i], out);
+                               strbuf_popchar(buf);
+                       }
                }
 
                child = index_readchild(node, '[');
                if (child) {
-                       strbuf_pushchar(buf, '[');
-                       index_searchwild__all(child, 0, buf, &key[i], out);
-                       strbuf_popchar(buf);
+                       if (strbuf_pushchar(buf, '[')) {
+                               index_searchwild__all(child, 0, buf, &key[i], out);
+                               strbuf_popchar(buf);
+                       }
                }
 
                if (key[i] == '\0') {
@@ -873,9 +883,10 @@ static void index_mm_dump_node(struct index_mm_node *node, struct strbuf *buf, i
                if (child == NULL)
                        continue;
 
-               strbuf_pushchar(buf, ch);
-               index_mm_dump_node(child, buf, fd);
-               strbuf_popchar(buf);
+               if (strbuf_pushchar(buf, ch)) {
+                       index_mm_dump_node(child, buf, fd);
+                       strbuf_popchar(buf);
+               }
        }
 
        strbuf_popchars(buf, pushed);
@@ -892,8 +903,8 @@ void index_mm_dump(struct index_mm *idx, int fd, const char *prefix)
                return;
 
        strbuf_init(&buf);
-       strbuf_pushchars(&buf, prefix);
-       index_mm_dump_node(root, &buf, fd);
+       if (strbuf_pushchars(&buf, prefix))
+               index_mm_dump_node(root, &buf, fd);
        strbuf_release(&buf);
 }
 
@@ -980,8 +991,7 @@ static void index_mm_searchwild_all(struct index_mm_node *node, int j, struct st
        while (node->prefix[j]) {
                ch = node->prefix[j];
 
-               strbuf_pushchar(buf, ch);
-               pushed++;
+               pushed += strbuf_pushchar(buf, ch);
                j++;
        }
 
@@ -991,13 +1001,16 @@ static void index_mm_searchwild_all(struct index_mm_node *node, int j, struct st
                if (!child)
                        continue;
 
-               strbuf_pushchar(buf, ch);
-               index_mm_searchwild_all(child, 0, buf, subkey, out);
-               strbuf_popchar(buf);
+               if (strbuf_pushchar(buf, ch)) {
+                       index_mm_searchwild_all(child, 0, buf, subkey, out);
+                       strbuf_popchar(buf);
+               }
        }
 
        if (node->values.len > 0) {
-               if (fnmatch(strbuf_str(buf), subkey, 0) == 0)
+               const char *s = strbuf_str(buf);
+
+               if (s != NULL && fnmatch(s, subkey, 0) == 0)
                        index_mm_searchwild_allvalues(node, out);
                else
                        index_mm_free_node(node);
@@ -1035,23 +1048,26 @@ static void index_mm_searchwild_node(struct index_mm_node *node, struct strbuf *
 
                child = index_mm_readchild(node, '*');
                if (child) {
-                       strbuf_pushchar(buf, '*');
-                       index_mm_searchwild_all(child, 0, buf, &key[i], out);
-                       strbuf_popchar(buf);
+                       if (strbuf_pushchar(buf, '*')) {
+                               index_mm_searchwild_all(child, 0, buf, &key[i], out);
+                               strbuf_popchar(buf);
+                       }
                }
 
                child = index_mm_readchild(node, '?');
                if (child) {
-                       strbuf_pushchar(buf, '?');
-                       index_mm_searchwild_all(child, 0, buf, &key[i], out);
-                       strbuf_popchar(buf);
+                       if (strbuf_pushchar(buf, '?')) {
+                               index_mm_searchwild_all(child, 0, buf, &key[i], out);
+                               strbuf_popchar(buf);
+                       }
                }
 
                child = index_mm_readchild(node, '[');
                if (child) {
-                       strbuf_pushchar(buf, '[');
-                       index_mm_searchwild_all(child, 0, buf, &key[i], out);
-                       strbuf_popchar(buf);
+                       if (strbuf_pushchar(buf, '[')) {
+                               index_mm_searchwild_all(child, 0, buf, &key[i], out);
+                               strbuf_popchar(buf);
+                       }
                }
 
                if (key[i] == '\0') {