2024-05-07 13:32:51

by Chuck Lever

[permalink] [raw]
Subject: [PATCH v2] SUNRPC: Fix gss_free_in_token_pages()

From: Chuck Lever <[email protected]>

Dan Carpenter says:
> Commit 5866efa8cbfb ("SUNRPC: Fix svcauth_gss_proxy_init()") from Oct
> 24, 2019 (linux-next), leads to the following Smatch static checker
> warning:
>
> net/sunrpc/auth_gss/svcauth_gss.c:1039 gss_free_in_token_pages()
> warn: iterator 'i' not incremented
>
> net/sunrpc/auth_gss/svcauth_gss.c
> 1034 static void gss_free_in_token_pages(struct gssp_in_token *in_token)
> 1035 {
> 1036 u32 inlen;
> 1037 int i;
> 1038
> --> 1039 i = 0;
> 1040 inlen = in_token->page_len;
> 1041 while (inlen) {
> 1042 if (in_token->pages[i])
> 1043 put_page(in_token->pages[i]);
> ^
> This puts page zero over and over.
>
> 1044 inlen -= inlen > PAGE_SIZE ? PAGE_SIZE : inlen;
> 1045 }
> 1046
> 1047 kfree(in_token->pages);
> 1048 in_token->pages = NULL;
> 1049 }

Based on the way that the ->pages[] array is constructed in
gss_read_proxy_verf(), we know that once the loop encounters a NULL
page pointer, the remaining array elements must also be NULL.

Reported-by: Dan Carpenter <[email protected]>
Suggested-by: Trond Myklebust <[email protected]>
Fixes: 5866efa8cbfb ("SUNRPC: Fix svcauth_gss_proxy_init()")
Signed-off-by: Chuck Lever <[email protected]>
---
net/sunrpc/auth_gss/svcauth_gss.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 24de94184700..96ab50eda9c2 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -1033,17 +1033,11 @@ svcauth_gss_proc_init_verf(struct cache_detail *cd, struct svc_rqst *rqstp,

static void gss_free_in_token_pages(struct gssp_in_token *in_token)
{
- u32 inlen;
int i;

i = 0;
- inlen = in_token->page_len;
- while (inlen) {
- if (in_token->pages[i])
- put_page(in_token->pages[i]);
- inlen -= inlen > PAGE_SIZE ? PAGE_SIZE : inlen;
- }
-
+ while (in_token->pages[i])
+ put_page(in_token->pages[i++]);
kfree(in_token->pages);
in_token->pages = NULL;
}

base-commit: 939cb14d51a150e3c12ef7a8ce0ba04ce6131bd2
--
2.44.0