diff mbox series

[net,5/7] net: tls: fix use-after-free with partial reads and async decrypt

Message ID 20240207011824.2609030-6-kuba@kernel.org (mailing list archive)
State Accepted
Commit 32b55c5ff9103b8508c1e04bfa5a08c64e7a925f
Delegated to: Netdev Maintainers
Headers show
Series net: tls: fix some issues with async encryption | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1064 this patch: 1064
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 6 of 6 maintainers
netdev/build_clang success Errors and warnings before: 1081 this patch: 1081
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1081 this patch: 1081
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 29 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-02-10--12-00 (tests: 1262)

Commit Message

Jakub Kicinski Feb. 7, 2024, 1:18 a.m. UTC 
From: Sabrina Dubroca <sd@queasysnail.net>

tls_decrypt_sg doesn't take a reference on the pages from clear_skb,
so the put_page() in tls_decrypt_done releases them, and we trigger
a use-after-free in process_rx_list when we try to read from the
partially-read skb.

Fixes: fd31f3996af2 ("tls: rx: decrypt into a fresh skb")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
This is pretty much Sabrina's patch just addressing my own
feedback, so I'm keeping her as the author.
---
CC: borisp@nvidia.com
CC: john.fastabend@gmail.com
---
 net/tls/tls_sw.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Simon Horman Feb. 9, 2024, 9:25 a.m. UTC | #1 
On Tue, Feb 06, 2024 at 05:18:22PM -0800, Jakub Kicinski wrote:
> From: Sabrina Dubroca <sd@queasysnail.net>
> 
> tls_decrypt_sg doesn't take a reference on the pages from clear_skb,
> so the put_page() in tls_decrypt_done releases them, and we trigger
> a use-after-free in process_rx_list when we try to read from the
> partially-read skb.
> 
> Fixes: fd31f3996af2 ("tls: rx: decrypt into a fresh skb")
> Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> ---
> This is pretty much Sabrina's patch just addressing my own
> feedback, so I'm keeping her as the author.

Reviewed-by: Simon Horman <horms@kernel.org>
diff mbox series

Patch

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 63bef5666e36..a6eff21ade23 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -63,6 +63,7 @@  struct tls_decrypt_ctx {
 	u8 iv[TLS_MAX_IV_SIZE];
 	u8 aad[TLS_MAX_AAD_SIZE];
 	u8 tail;
+	bool free_sgout;
 	struct scatterlist sg[];
 };
 
@@ -187,7 +188,6 @@  static void tls_decrypt_done(void *data, int err)
 	struct aead_request *aead_req = data;
 	struct crypto_aead *aead = crypto_aead_reqtfm(aead_req);
 	struct scatterlist *sgout = aead_req->dst;
-	struct scatterlist *sgin = aead_req->src;
 	struct tls_sw_context_rx *ctx;
 	struct tls_decrypt_ctx *dctx;
 	struct tls_context *tls_ctx;
@@ -224,7 +224,7 @@  static void tls_decrypt_done(void *data, int err)
 	}
 
 	/* Free the destination pages if skb was not decrypted inplace */
-	if (sgout != sgin) {
+	if (dctx->free_sgout) {
 		/* Skip the first S/G entry as it points to AAD */
 		for_each_sg(sg_next(sgout), sg, UINT_MAX, pages) {
 			if (!sg)
@@ -1583,6 +1583,7 @@  static int tls_decrypt_sg(struct sock *sk, struct iov_iter *out_iov,
 	} else if (out_sg) {
 		memcpy(sgout, out_sg, n_sgout * sizeof(*sgout));
 	}
+	dctx->free_sgout = !!pages;
 
 	/* Prepare and submit AEAD request */
 	err = tls_do_decryption(sk, sgin, sgout, dctx->iv,