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authorChuck Lever <chuck.lever@oracle.com>2020-07-24 17:08:57 -0400
committerChuck Lever <chuck.lever@oracle.com>2020-07-24 17:10:23 -0400
commit986a4b63d3bc5f2c0eb4083b05aff2bf883b7b2f (patch)
treee10a0734385d66e46ed12116a15f3c3676681021
parentdf60446cd1fb487becd1f36f4c0da9e0e523c0cf (diff)
SUNRPC: Fix ("SUNRPC: Add "@len" parameter to gss_unwrap()")
Braino when converting "buf->len -=" to "buf->len = len -". The result is under-estimation of the ralign and rslack values. On krb5p mounts, this has caused READDIR to fail with EIO, and KASAN splats when decoding READLINK replies. As a result of fixing this oversight, the gss_unwrap method now returns a buf->len that can be shorter than priv_len for small RPC messages. The additional adjustment done in unwrap_priv_data() can underflow buf->len. This causes the nfsd_request_too_large check to fail during some NFSv3 operations. Reported-by: Marian Rainer-Harbach Reported-by: Pierre Sauter <pierre.sauter@stwm.de> BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1886277 Fixes: 31c9590ae468 ("SUNRPC: Add "@len" parameter to gss_unwrap()") Reviewed-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
-rw-r--r--net/sunrpc/auth_gss/gss_krb5_wrap.c2
-rw-r--r--net/sunrpc/auth_gss/svcauth_gss.c1
2 files changed, 1 insertions, 2 deletions
diff --git a/net/sunrpc/auth_gss/gss_krb5_wrap.c b/net/sunrpc/auth_gss/gss_krb5_wrap.c
index cf0fd170ac18..90b8329fef82 100644
--- a/net/sunrpc/auth_gss/gss_krb5_wrap.c
+++ b/net/sunrpc/auth_gss/gss_krb5_wrap.c
@@ -584,7 +584,7 @@ gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, int len,
buf->head[0].iov_len);
memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen);
buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
- buf->len = len - GSS_KRB5_TOK_HDR_LEN + headskip;
+ buf->len = len - (GSS_KRB5_TOK_HDR_LEN + headskip);
/* Trim off the trailing "extra count" and checksum blob */
xdr_buf_trim(buf, ec + GSS_KRB5_TOK_HDR_LEN + tailskip);
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 7d83f54aaaa6..258b04372f85 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -990,7 +990,6 @@ unwrap_priv_data(struct svc_rqst *rqstp, struct xdr_buf *buf, u32 seq, struct gs
maj_stat = gss_unwrap(ctx, 0, priv_len, buf);
pad = priv_len - buf->len;
- buf->len -= pad;
/* The upper layers assume the buffer is aligned on 4-byte boundaries.
* In the krb5p case, at least, the data ends up offset, so we need to
* move it around. */