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From: Anton Moryakov <ant.v.moryakov@gmail.com>
To: chengzhihao1@huawei.com, linux-mtd@lists.infradead.org
Cc: Anton Moryakov <ant.v.moryakov@gmail.com>
Subject: [PATCH mtd-utils] misc-utils: Fix integer overflow in docfdisk.c
Date: Tue, 17 Dec 2024 15:44:22 +0300	[thread overview]
Message-ID: <20241217124422.245489-1-ant.v.moryakov@gmail.com> (raw)

Report of the static analyzer:
Possible integer underflow: left operand is tainted. An integer underflow may occur due to arithmetic operation (subtraction) between variable 'block' and value '1', when 'block' is tainted { [-2147483648, 2147483647] }

Corrections explained:
Added the block <= 0 check, which prevents integer underflow when calculating block - 1 and ensures that block is always positive.

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>

---
 misc-utils/docfdisk.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/misc-utils/docfdisk.c b/misc-utils/docfdisk.c
index 486ce29..e473ceb 100644
--- a/misc-utils/docfdisk.c
+++ b/misc-utils/docfdisk.c
@@ -255,6 +255,10 @@ int main(int argc, char **argv)
 		ip->firstUnit = cpu_to_le32(block);
 		if (!nblocks[i])
 			nblocks[i] = totblocks - block;
+		if (block <= 0) {
+			fprintf(stderr, "Error: Invalid block value (%d). Block must be greater than 0.\n", block);
+			return -1;
+		}
 		ip->virtualUnits = cpu_to_le32(nblocks[i]);
 		block += nblocks[i];
 		ip->lastUnit = cpu_to_le32(block-1);
-- 
2.30.2


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             reply	other threads:[~2024-12-17 12:44 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-17 12:44 Anton Moryakov [this message]
2024-12-18  1:30 ` [PATCH mtd-utils] misc-utils: Fix integer overflow in docfdisk.c Zhihao Cheng

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