47 lines
1.4 KiB
Diff
47 lines
1.4 KiB
Diff
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From 6c88722c175adca5b1a72bcc770f94674405b7f4 Mon Sep 17 00:00:00 2001
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From: Samanta Navarro <ferivoz@riseup.net>
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Date: Fri, 13 Jan 2023 11:53:41 +0000
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Subject: [PATCH] mkswap: do not use uninitialized stack value
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If blkdev_get_size fails, then size is not set. Exit with an error code
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and indicate what went wrong instead of continuing with random stack
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content.
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Proof of Concept:
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```
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$ mkswap /dev/null
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mkswap: warning: truncating swap area to 17179869180 KiB
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mkswap: /dev/null: insecure permissions 0666, fix with: chmod 0600 /dev/null
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mkswap: unable to assign device to libblkid probe
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```
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The first output line depends on stack content and sometimes does not
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show up at all. Abort operation if argument is neither regular file nor
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block device.
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Signed-off-by: Samanta Navarro <ferivoz@riseup.net>
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---
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disk-utils/mkswap.c | 5 +++--
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1 file changed, 3 insertions(+), 2 deletions(-)
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diff --git a/disk-utils/mkswap.c b/disk-utils/mkswap.c
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index 7e2164704..bd0230177 100644
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--- a/disk-utils/mkswap.c
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+++ b/disk-utils/mkswap.c
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@@ -345,8 +345,9 @@ static unsigned long long get_size(const struct mkswap_control *ctl)
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fd = open(ctl->devname, O_RDONLY);
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if (fd < 0)
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err(EXIT_FAILURE, _("cannot open %s"), ctl->devname);
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- if (blkdev_get_size(fd, &size) == 0)
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- size /= ctl->pagesize;
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+ if (blkdev_get_size(fd, &size) < 0)
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+ err(EXIT_FAILURE, _("cannot determine size of %s"), ctl->devname);
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+ size /= ctl->pagesize;
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close(fd);
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return size;
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--
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2.27.0
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