cmd: nvedit: env_get_f must check for env_get_char error codes

env_get_f calls env_get_char to load single characters from the
environment. However, the return value of env_get_char was not
checked for errors. Now if the env driver does not support the
.get_char call, env_get_f did not notice this and looped over the
whole size of the environment, calling env_get_char over 8000
times with the default settings, just to return an error in the
end.

Fix this by checking if env_get_char returns < 0.

Signed-off-by: Simon Goldschmidt <sgoldschmidt@de.pepperl-fuchs.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>

diff --git a/cmd/nvedit.c b/cmd/nvedit.c
index a690d743cd4667cd4859c40bd64fcad20bbc4978..4cb25b824865f9aad6da83b5f63ee9312b3d8b4d 100644 (file)
--- a/cmd/nvedit.c
+++ b/cmd/nvedit.c
@@ -650,12 +650,14 @@ char *env_get(const char *name)
  */
 int env_get_f(const char *name, char *buf, unsigned len)
 {
-       int i, nxt;
+       int i, nxt, c;
 
        for (i = 0; env_get_char(i) != '\0'; i = nxt + 1) {
                int val, n;
 
-               for (nxt = i; env_get_char(nxt) != '\0'; ++nxt) {
+               for (nxt = i; (c = env_get_char(nxt)) != '\0'; ++nxt) {
+                       if (c < 0)
+                               return c;
                        if (nxt >= CONFIG_ENV_SIZE)
                                return -1;
                }
@@ -666,7 +668,10 @@ int env_get_f(const char *name, char *buf, unsigned len)
 
                /* found; copy out */
                for (n = 0; n < len; ++n, ++buf) {
-                       *buf = env_get_char(val++);
+                       c = env_get_char(val++);
+                       if (c < 0)
+                               return c;
+                       *buf = c;
                        if (*buf == '\0')
                                return n;
                }