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From 616db6ddcacd25e4c3a771cd317373971c9055ed Mon Sep 17 00:00:00 2001
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From: =?UTF-8?q?Mantas=20Mikul=C4=97nas?= <grawity@gmail.com>
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Date: Fri, 29 Jan 2016 23:36:08 +0200
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Subject: [PATCH] basic: fix touch() creating files with 07777 mode
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mode_t is unsigned, so MODE_INVALID < 0 can never be true.
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This fixes a possible DoS where any user could fill /run by writing to
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a world-writable /run/systemd/show-status.
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Cherry-picked from: 06eeacb6fe029804f296b065b3ce91e796e1cd0e
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Resolves: #1416062
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---
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 src/shared/util.c | 3 ++-
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 1 file changed, 2 insertions(+), 1 deletion(-)
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diff --git a/src/shared/util.c b/src/shared/util.c
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index 66729f70e..1070e32c4 100644
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--- a/src/shared/util.c
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+++ b/src/shared/util.c
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@@ -3908,7 +3908,8 @@ int touch_file(const char *path, bool parents, usec_t stamp, uid_t uid, gid_t gi
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         if (parents)
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                 mkdir_parents(path, 0755);
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-        fd = open(path, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY, mode > 0 ? mode : 0644);
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+        fd = open(path, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY,
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+                        (mode == 0 || mode == MODE_INVALID) ? 0644 : mode);
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         if (fd < 0)
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                 return -errno;
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