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proc/sysctl: make protected_* world readable 

protected_* files have 600 permissions which prevents non-superuser from
reading them.

Container like "AWS greengrass" refuse to launch unless
protected_hardlinks and protected_symlinks are set.  When containers like
these run with "userns-remap" or "--user" mapping container's root to
non-superuser on host, they fail to run due to denied read access to these
files.

As these protections are hardly a secret, and do not possess any security
risk, making them world readable.

Though above greengrass usecase needs read access to only
protected_hardlinks and protected_symlinks files, setting all other
protected_* files to 644 to keep consistency.

Link: http://lkml.kernel.org/r/20200709235115.56954-1-jpitti@cisco.com
Fixes: 800179c9b8 ("fs: add link restrictions")
Signed-off-by: Julius Hemanth Pitti <jpitti@cisco.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Julius Hemanth Pitti 2022-05-13 16:58:15 -07:00 committed by Andrew Morton
parent 25d9767831
commit c7031c1440
1 changed files with 4 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
fs/namei.c
View File

@ -1031,7 +1031,7 @@ static struct ctl_table namei_sysctls[] = {
.procname = "protected_symlinks",
.data = &sysctl_protected_symlinks,
.maxlen = sizeof(int),
.mode = 0600,
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
@ -1040,7 +1040,7 @@ static struct ctl_table namei_sysctls[] = {
.procname = "protected_hardlinks",
.data = &sysctl_protected_hardlinks,
.maxlen = sizeof(int),
.mode = 0600,
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_ONE,
@ -1049,7 +1049,7 @@ static struct ctl_table namei_sysctls[] = {
.procname = "protected_fifos",
.data = &sysctl_protected_fifos,
.maxlen = sizeof(int),
.mode = 0600,
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,
@ -1058,7 +1058,7 @@ static struct ctl_table namei_sysctls[] = {
.procname = "protected_regular",
.data = &sysctl_protected_regular,
.maxlen = sizeof(int),
.mode = 0600,
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = SYSCTL_ZERO,
.extra2 = SYSCTL_TWO,