From c7031c144043c5b9a9b8827aaf44a67937559418 Mon Sep 17 00:00:00 2001 From: Julius Hemanth Pitti Date: Fri, 13 May 2022 16:58:15 -0700 Subject: [PATCH] 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: 800179c9b8a1 ("fs: add link restrictions") Signed-off-by: Julius Hemanth Pitti Acked-by: Kees Cook Acked-by: Luis Chamberlain Cc: Iurii Zaikin Cc: Ingo Molnar Cc: Al Viro Signed-off-by: Andrew Morton --- fs/namei.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/fs/namei.c b/fs/namei.c index 509657f..5e05571 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -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, -- 2.7.4