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Preserve nosymfollow across bind-mount flag fixups #770

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Preserve nosymfollow across bind-mount flag fixups #770

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6 changes: 6 additions & 0 deletions bind-mount.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,11 @@
#include "utils.h"
#include "bind-mount.h"

/* MS_NOSYMFOLLOW was added in Linux 5.10 */
#ifndef MS_NOSYMFOLLOW
#define MS_NOSYMFOLLOW 256
#endif

static char *
skip_token (char *line, bool eat_whitespace)
{
Expand Down Expand Up @@ -93,6 +98,7 @@ decode_mountoptions (const char *options)
{ MS_NOSUID, "nosuid" },
{ MS_NODEV, "nodev" },
{ MS_NOEXEC, "noexec" },
{ MS_NOSYMFOLLOW, "nosymfollow" },
{ MS_NOATIME, "noatime" },
{ MS_NODIRATIME, "nodiratime" },
{ MS_RELATIME, "relatime" },
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6 changes: 6 additions & 0 deletions tests/test-run.sh
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Expand Up @@ -91,6 +91,12 @@ else
fi
ok "--symlink doesn't overwrite a conflicting symlink"

# A nosymfollow source must stay nosymfollow across the fixup remount
if unshare -rm sh -c 'mount -t tmpfs -o nosymfollow tmpfs /tmp && : >/tmp/x && ln -s x /tmp/l && '"$BWRAP"' --ro-bind / / cat /tmp/l' 2>/dev/null; then
assert_not_reached "nosymfollow dropped by bind fixup; symlink was followed"
fi
ok "bind mount preserves nosymfollow"

# Test devices
$RUN --unshare-pid --dev /dev ls -al /dev/{stdin,stdout,stderr,null,random,urandom,fd,core} >/dev/null
ok "all expected devices were created"
Expand Down