[ 66/71] rpc: comment on linux_cred encoding, treat all as unsigned
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2013-09-29 19:34:33
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3.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: "J. Bruce Fields" <redacted> commit 6a36978e6931e6601be586eb313375335f2cfaa3 upstream. The encoding of linux creds is a bit confusing. Also: I think in practice it doesn't really matter whether we treat any of these things as signed or unsigned, but unsigned seems more straightforward: uid_t/gid_t are unsigned and it simplifies the ngroups overflow check. Tested-by: Simo Sorce <redacted> Signed-off-by: J. Bruce Fields <redacted> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/sunrpc/auth_gss/gss_rpc_xdr.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-)
--- a/net/sunrpc/auth_gss/gss_rpc_xdr.c
+++ b/net/sunrpc/auth_gss/gss_rpc_xdr.c@@ -166,14 +166,15 @@ static int dummy_dec_opt_array(struct xd return 0; } -static int get_s32(struct xdr_stream *xdr, s32 *res) +static int get_host_u32(struct xdr_stream *xdr, u32 *res) { __be32 *p; p = xdr_inline_decode(xdr, 4); if (!p) return -EINVAL; - memcpy(res, p, sizeof(s32)); + /* Contents of linux creds are all host-endian: */ + memcpy(res, p, sizeof(u32)); return 0; }
@@ -182,8 +183,9 @@ static int gssx_dec_linux_creds(struct x { u32 length; __be32 *p; - s32 tmp; - int N, i, err; + u32 tmp; + u32 N; + int i, err; p = xdr_inline_decode(xdr, 4); if (unlikely(p == NULL))
@@ -195,19 +197,19 @@ static int gssx_dec_linux_creds(struct x return -ENOSPC; /* uid */ - err = get_s32(xdr, &tmp); + err = get_host_u32(xdr, &tmp); if (err) return err; creds->cr_uid = make_kuid(&init_user_ns, tmp); /* gid */ - err = get_s32(xdr, &tmp); + err = get_host_u32(xdr, &tmp); if (err) return err; creds->cr_gid = make_kgid(&init_user_ns, tmp); /* number of additional gid's */ - err = get_s32(xdr, &tmp); + err = get_host_u32(xdr, &tmp); if (err) return err; N = tmp;
@@ -220,7 +222,7 @@ static int gssx_dec_linux_creds(struct x /* gid's */ for (i = 0; i < N; i++) { kgid_t kgid; - err = get_s32(xdr, &tmp); + err = get_host_u32(xdr, &tmp); if (err) goto out_free_groups; err = -EINVAL;