depmod: fix string overflow

Use scratchbuf to fix issue with strcpy that may overflow the buffer we
declared in the stack.

diff --git a/tools/depmod.c b/tools/depmod.c
index a2e07c1..ad01f66 100644 (file)
--- a/tools/depmod.c
+++ b/tools/depmod.c
@@ -35,6 +35,7 @@
 #include <shared/hash.h>
 #include <shared/macro.h>
 #include <shared/util.h>
+#include <shared/scratchbuf.h>
 
 #include <libkmod/libkmod.h>
 
@@ -1920,9 +1921,12 @@ static int output_symbols_bin(struct depmod *depmod, FILE *out)
 {
        struct index_node *idx;
        char alias[1024];
+       _cleanup_(scratchbuf_release) struct scratchbuf salias =
+               SCRATCHBUF_INITIALIZER(alias);
        size_t baselen = sizeof("symbol:") - 1;
        struct hash_iter iter;
        const void *v;
+       int ret = 0;
 
        if (out == stdout)
                return 0;
@@ -1932,16 +1936,24 @@ static int output_symbols_bin(struct depmod *depmod, FILE *out)
                return -ENOMEM;
 
        memcpy(alias, "symbol:", baselen);
+
        hash_iter_init(depmod->symbols, &iter);
 
        while (hash_iter_next(&iter, NULL, &v)) {
                int duplicate;
                const struct symbol *sym = v;
+               size_t len;
 
                if (sym->owner == NULL)
                        continue;
 
-               strcpy(alias + baselen, sym->name);
+               len = strlen(sym->name);
+
+               if (scratchbuf_alloc(&salias, baselen + len + 1) < 0) {
+                       ret = -ENOMEM;
+                       goto err_scratchbuf;
+               }
+               memcpy(scratchbuf_str(&salias) + baselen, sym->name, len + 1);
                duplicate = index_insert(idx, alias, sym->owner->modname,
                                                        sym->owner->idx);
 
@@ -1951,9 +1963,14 @@ static int output_symbols_bin(struct depmod *depmod, FILE *out)
        }
 
        index_write(idx, out);
+
+err_scratchbuf:
        index_destroy(idx);
 
-       return 0;
+       if (ret < 0)
+               ERR("output symbols: %s\n", strerror(-ret));
+
+       return ret;
 }
 
 static int output_builtin_bin(struct depmod *depmod, FILE *out)