linux-kernel - [PATCH AUTOSEL 6.1 19/39] efi: fix memory leak in krealloc failure handling

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Date:   Sun, 29 Oct 2023 18:56:51 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Kuan-Wei Chiu <visitorckw@...il.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Sasha Levin <sashal@...nel.org>, linux-efi@...r.kernel.org
Subject: [PATCH AUTOSEL 6.1 19/39] efi: fix memory leak in krealloc failure handling

From: Kuan-Wei Chiu <visitorckw@...il.com>

[ Upstream commit 0d3ad1917996839a5042d18f04e41915cfa1b74a ]

In the previous code, there was a memory leak issue where the
previously allocated memory was not freed upon a failed krealloc
operation. This patch addresses the problem by releasing the old memory
before setting the pointer to NULL in case of a krealloc failure. This
ensures that memory is properly managed and avoids potential memory
leaks.

Signed-off-by: Kuan-Wei Chiu <visitorckw@...il.com>
Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/firmware/efi/efi.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index b43e5e6ddaf6e..b7c0e8cc0764f 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -245,9 +245,13 @@ static __init int efivar_ssdt_load(void)
 		if (status == EFI_NOT_FOUND) {
 			break;
 		} else if (status == EFI_BUFFER_TOO_SMALL) {
-			name = krealloc(name, name_size, GFP_KERNEL);
-			if (!name)
+			efi_char16_t *name_tmp =
+				krealloc(name, name_size, GFP_KERNEL);
+			if (!name_tmp) {
+				kfree(name);
 				return -ENOMEM;
+			}
+			name = name_tmp;
 			continue;
 		}
 
-- 
2.42.0