SUNRPC: auth_gss: fix memory leaks in XDR decoding error paths

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commit 3e6397b056 upstream.

The gssx_dec_ctx(), gssx_dec_status(), and gssx_dec_name()
functions allocate memory via gssx_dec_buffer(), which calls
kmemdup(). When a subsequent decode operation fails, these
functions return immediately without freeing previously
allocated buffers, causing memory leaks.

The leak in gssx_dec_ctx() is particularly relevant because
the caller (gssp_accept_sec_context_upcall) initializes several
buffer length fields to non-zero values, resulting in memory
allocation:

    struct gssx_ctx rctxh = {
        .exported_context_token.len = GSSX_max_output_handle_sz,
        .mech.len = GSS_OID_MAX_LEN,
        .src_name.display_name.len = GSSX_max_princ_sz,
        .targ_name.display_name.len = GSSX_max_princ_sz
    };

If, for example, gssx_dec_name() succeeds for src_name but
fails for targ_name, the memory allocated for
exported_context_token, mech, and src_name.display_name
remains unreferenced and cannot be reclaimed.

Add error handling with goto-based cleanup to free any
previously allocated buffers before returning an error.

Reported-by: Xingjing Deng <micro6947@gmail.com>
Closes: https://lore.kernel.org/linux-nfs/CAK+ZN9qttsFDu6h1FoqGadXjMx1QXqPMoYQ=6O9RY4SxVTvKng@mail.gmail.com/
Fixes: 1d658336b0 ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth")
Cc: stable@vger.kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Chuck Lever 2025-12-26 10:15:32 -05:00 • committed by Sasha Levin

parent 6bd22de73c

commit b4af380684

1 changed files with 64 additions and 18 deletions

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net/sunrpc/auth_gss/gss_rpc_xdr.c

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