Re: [PATCH 1/2] security: let security modules use PTRACE_MODE_* with bitmasks
From: Casey Schaufler <casey@schaufler-ca.com>
Date: 2015-12-07 21:52:36
Also in:
linux-mm, lkml
On 12/7/2015 1:25 PM, Jann Horn wrote:
It looks like smack and yama weren't aware that the ptrace mode can have flags ORed into it - PTRACE_MODE_NOAUDIT until now, but only for /proc/$pid/stat, and with the PTRACE_MODE_*CREDS patch, all modes have flags ORed into them. Signed-off-by: Jann Horn <redacted>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
quoted hunk ↗ jump to hunk
--- security/smack/smack_lsm.c | 8 +++----- security/yama/yama_lsm.c | 4 ++-- 2 files changed, 5 insertions(+), 7 deletions(-)diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index ff81026..7c57c7f 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c@@ -398,12 +398,10 @@ static int smk_copy_relabel(struct list_head *nhead, struct list_head *ohead, */ static inline unsigned int smk_ptrace_mode(unsigned int mode) { - switch (mode) { - case PTRACE_MODE_READ: - return MAY_READ; - case PTRACE_MODE_ATTACH: + if (mode & PTRACE_MODE_ATTACH) return MAY_READWRITE; - } + if (mode & PTRACE_MODE_READ) + return MAY_READ; return 0; }diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c index d3c19c9..cb6ed10 100644 --- a/security/yama/yama_lsm.c +++ b/security/yama/yama_lsm.c@@ -281,7 +281,7 @@ static int yama_ptrace_access_check(struct task_struct *child, int rc = 0; /* require ptrace target be a child of ptracer on attach */ - if (mode == PTRACE_MODE_ATTACH) { + if (mode & PTRACE_MODE_ATTACH) { switch (ptrace_scope) { case YAMA_SCOPE_DISABLED: /* No additional restrictions. */@@ -307,7 +307,7 @@ static int yama_ptrace_access_check(struct task_struct *child, } } - if (rc) { + if (rc && (mode & PTRACE_MODE_NOAUDIT) == 0) { printk_ratelimited(KERN_NOTICE "ptrace of pid %d was attempted by: %s (pid %d)\n", child->pid, current->comm, current->pid);
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