From: Chuck Lever Date: Fri, 26 Dec 2025 15:15:32 +0000 (-0500) Subject: SUNRPC: auth_gss: fix memory leaks in XDR decoding error paths X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3e6397b056335cc56ef0e9da36c95946a19f5118;p=thirdparty%2Fkernel%2Flinux.git SUNRPC: auth_gss: fix memory leaks in XDR decoding error paths 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 Closes: https://lore.kernel.org/linux-nfs/CAK+ZN9qttsFDu6h1FoqGadXjMx1QXqPMoYQ=6O9RY4SxVTvKng@mail.gmail.com/ Fixes: 1d658336b05f ("SUNRPC: Add RPC based upcall mechanism for RPCGSS auth") Cc: stable@vger.kernel.org Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever --- diff --git a/net/sunrpc/auth_gss/gss_rpc_xdr.c b/net/sunrpc/auth_gss/gss_rpc_xdr.c index 7d2cdc2bd374e..f320c0a8e6049 100644 --- a/net/sunrpc/auth_gss/gss_rpc_xdr.c +++ b/net/sunrpc/auth_gss/gss_rpc_xdr.c @@ -320,29 +320,47 @@ static int gssx_dec_status(struct xdr_stream *xdr, /* status->minor_status */ p = xdr_inline_decode(xdr, 8); - if (unlikely(p == NULL)) - return -ENOSPC; + if (unlikely(p == NULL)) { + err = -ENOSPC; + goto out_free_mech; + } p = xdr_decode_hyper(p, &status->minor_status); /* status->major_status_string */ err = gssx_dec_buffer(xdr, &status->major_status_string); if (err) - return err; + goto out_free_mech; /* status->minor_status_string */ err = gssx_dec_buffer(xdr, &status->minor_status_string); if (err) - return err; + goto out_free_major_status_string; /* status->server_ctx */ err = gssx_dec_buffer(xdr, &status->server_ctx); if (err) - return err; + goto out_free_minor_status_string; /* we assume we have no options for now, so simply consume them */ /* status->options */ err = dummy_dec_opt_array(xdr, &status->options); + if (err) + goto out_free_server_ctx; + return 0; + +out_free_server_ctx: + kfree(status->server_ctx.data); + status->server_ctx.data = NULL; +out_free_minor_status_string: + kfree(status->minor_status_string.data); + status->minor_status_string.data = NULL; +out_free_major_status_string: + kfree(status->major_status_string.data); + status->major_status_string.data = NULL; +out_free_mech: + kfree(status->mech.data); + status->mech.data = NULL; return err; } @@ -505,28 +523,35 @@ static int gssx_dec_name(struct xdr_stream *xdr, /* name->name_type */ err = gssx_dec_buffer(xdr, &dummy_netobj); if (err) - return err; + goto out_free_display_name; /* name->exported_name */ err = gssx_dec_buffer(xdr, &dummy_netobj); if (err) - return err; + goto out_free_display_name; /* name->exported_composite_name */ err = gssx_dec_buffer(xdr, &dummy_netobj); if (err) - return err; + goto out_free_display_name; /* we assume we have no attributes for now, so simply consume them */ /* name->name_attributes */ err = dummy_dec_nameattr_array(xdr, &dummy_name_attr_array); if (err) - return err; + goto out_free_display_name; /* we assume we have no options for now, so simply consume them */ /* name->extensions */ err = dummy_dec_opt_array(xdr, &dummy_option_array); + if (err) + goto out_free_display_name; + return 0; + +out_free_display_name: + kfree(name->display_name.data); + name->display_name.data = NULL; return err; } @@ -649,32 +674,34 @@ static int gssx_dec_ctx(struct xdr_stream *xdr, /* ctx->state */ err = gssx_dec_buffer(xdr, &ctx->state); if (err) - return err; + goto out_free_exported_context_token; /* ctx->need_release */ err = gssx_dec_bool(xdr, &ctx->need_release); if (err) - return err; + goto out_free_state; /* ctx->mech */ err = gssx_dec_buffer(xdr, &ctx->mech); if (err) - return err; + goto out_free_state; /* ctx->src_name */ err = gssx_dec_name(xdr, &ctx->src_name); if (err) - return err; + goto out_free_mech; /* ctx->targ_name */ err = gssx_dec_name(xdr, &ctx->targ_name); if (err) - return err; + goto out_free_src_name; /* ctx->lifetime */ p = xdr_inline_decode(xdr, 8+8); - if (unlikely(p == NULL)) - return -ENOSPC; + if (unlikely(p == NULL)) { + err = -ENOSPC; + goto out_free_targ_name; + } p = xdr_decode_hyper(p, &ctx->lifetime); /* ctx->ctx_flags */ @@ -683,17 +710,36 @@ static int gssx_dec_ctx(struct xdr_stream *xdr, /* ctx->locally_initiated */ err = gssx_dec_bool(xdr, &ctx->locally_initiated); if (err) - return err; + goto out_free_targ_name; /* ctx->open */ err = gssx_dec_bool(xdr, &ctx->open); if (err) - return err; + goto out_free_targ_name; /* we assume we have no options for now, so simply consume them */ /* ctx->options */ err = dummy_dec_opt_array(xdr, &ctx->options); + if (err) + goto out_free_targ_name; + + return 0; +out_free_targ_name: + kfree(ctx->targ_name.display_name.data); + ctx->targ_name.display_name.data = NULL; +out_free_src_name: + kfree(ctx->src_name.display_name.data); + ctx->src_name.display_name.data = NULL; +out_free_mech: + kfree(ctx->mech.data); + ctx->mech.data = NULL; +out_free_state: + kfree(ctx->state.data); + ctx->state.data = NULL; +out_free_exported_context_token: + kfree(ctx->exported_context_token.data); + ctx->exported_context_token.data = NULL; return err; }