From: Karel Zak <kzak@redhat.com>
Date: Thu, 26 Dec 2024 11:45:31 +0000 (+0100)
Subject: hardlink: fix memory corruption (size calculation)
X-Git-Tag: v2.42-start~107^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=70c1ffbdf4ecac30536e1af13764adbd883a161d;p=thirdparty%2Futil-linux.git

hardlink: fix memory corruption (size calculation)

The current code rounds down the values for readsiz and blocksmax,
which is incorrect. The sizes must be large enough to match the files.

Addresses: https://github.com/util-linux/util-linux/issues/3330
Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/lib/fileeq.c b/lib/fileeq.c
index 1f7f90ccb..d0ba77cc3 100644
--- a/lib/fileeq.c
+++ b/lib/fileeq.c
@@ -272,12 +272,12 @@ size_t ul_fileeq_set_size(struct ul_fileeq *eq, uint64_t filesiz,
 		nreads = filesiz / readsiz;
 		/* enlarge readsize for large files */
 		if (nreads > maxdigs)
-			readsiz = filesiz / maxdigs;
+			readsiz = (filesiz + maxdigs - 1) / maxdigs;
 		break;
 	}
 
 	eq->readsiz = readsiz;
-	eq->blocksmax = filesiz / readsiz;
+	eq->blocksmax = (filesiz + readsiz - 1) / readsiz;
 
 	DBG(EQ, ul_debugobj(eq, "set sizes: filesiz=%ju, maxblocks=%" PRIu64 ", readsiz=%zu",
 				eq->filesiz, eq->blocksmax, eq->readsiz));