linux-kernel - [PATCH] efi: fix memory leak in krealloc failure handling

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Message-Id: <20230924142633.1090000-1-visitorckw@gmail.com>
Date:   Sun, 24 Sep 2023 22:26:33 +0800
From:   Kuan-Wei Chiu <visitorckw@...il.com>
To:     ardb@...nel.org
Cc:     linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
        Kuan-Wei Chiu <visitorckw@...il.com>
Subject: [PATCH] efi: fix memory leak in krealloc failure handling

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>
---
 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 ce20a60676f0..1974f0ad32ba 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -273,9 +273,13 @@ 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;
 		}
 
-- 
2.25.1