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| author | Chuck Lever <chuck.lever@oracle.com> | 2020-07-24 23:08:57 +0200 |
|---|---|---|
| committer | Chuck Lever <chuck.lever@oracle.com> | 2020-07-24 23:10:23 +0200 |
| commit | 986a4b63d3bc5f2c0eb4083b05aff2bf883b7b2f (patch) | |
| tree | e10a0734385d66e46ed12116a15f3c3676681021 /net/sunrpc/auth_gss | |
| parent | nfsd: avoid a NULL dereference in __cld_pipe_upcall() (diff) | |
| download | linux-986a4b63d3bc5f2c0eb4083b05aff2bf883b7b2f.tar.xz linux-986a4b63d3bc5f2c0eb4083b05aff2bf883b7b2f.zip | |
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>
Diffstat (limited to 'net/sunrpc/auth_gss')
| -rw-r--r-- | net/sunrpc/auth_gss/gss_krb5_wrap.c | 2 | ||||
| -rw-r--r-- | net/sunrpc/auth_gss/svcauth_gss.c | 1 |
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. */ |