diff options
| -rw-r--r-- | fs/exec.c | 10 | ||||
| -rw-r--r-- | include/linux/sched.h | 5 | ||||
| -rw-r--r-- | kernel/sysctl.c | 37 |
3 files changed, 45 insertions, 7 deletions
diff --git a/fs/exec.c b/fs/exec.c index 95aae3f9c036..5af8390e0fae 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -2002,17 +2002,17 @@ static void coredump_finish(struct mm_struct *mm) void set_dumpable(struct mm_struct *mm, int value) { switch (value) { - case 0: + case SUID_DUMPABLE_DISABLED: clear_bit(MMF_DUMPABLE, &mm->flags); smp_wmb(); clear_bit(MMF_DUMP_SECURELY, &mm->flags); break; - case 1: + case SUID_DUMPABLE_ENABLED: set_bit(MMF_DUMPABLE, &mm->flags); smp_wmb(); clear_bit(MMF_DUMP_SECURELY, &mm->flags); break; - case 2: + case SUID_DUMPABLE_SAFE: set_bit(MMF_DUMP_SECURELY, &mm->flags); smp_wmb(); set_bit(MMF_DUMPABLE, &mm->flags); @@ -2025,7 +2025,7 @@ static int __get_dumpable(unsigned long mm_flags) int ret; ret = mm_flags & MMF_DUMPABLE_MASK; - return (ret >= 2) ? 2 : ret; + return (ret > SUID_DUMPABLE_ENABLED) ? SUID_DUMPABLE_SAFE : ret; } int get_dumpable(struct mm_struct *mm) @@ -2142,7 +2142,7 @@ void do_coredump(long signr, int exit_code, struct pt_regs *regs) * so we dump it as root in mode 2, and only into a controlled * environment (pipe handler or fully qualified path). */ - if (__get_dumpable(cprm.mm_flags) == 2) { + if (__get_dumpable(cprm.mm_flags) == SUID_DUMPABLE_SAFE) { /* Setuid core dump mode */ flag = O_EXCL; /* Stop rewrite attacks */ cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */ diff --git a/include/linux/sched.h b/include/linux/sched.h index a721cef7e2d4..1e26a5e45aa6 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -406,6 +406,11 @@ static inline void arch_pick_mmap_layout(struct mm_struct *mm) {} extern void set_dumpable(struct mm_struct *mm, int value); extern int get_dumpable(struct mm_struct *mm); +/* get/set_dumpable() values */ +#define SUID_DUMPABLE_DISABLED 0 +#define SUID_DUMPABLE_ENABLED 1 +#define SUID_DUMPABLE_SAFE 2 + /* mm flags */ /* dumpable bits */ #define MMF_DUMPABLE 0 /* core dump is permitted */ diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 4ab11879aeb4..b46f496405e4 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -174,6 +174,11 @@ static int proc_dointvec_minmax_sysadmin(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); #endif +static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos); +static int proc_dostring_coredump(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos); + #ifdef CONFIG_MAGIC_SYSRQ /* Note: sysrq code uses it's own private copy */ static int __sysrq_enabled = SYSRQ_DEFAULT_ENABLE; @@ -410,7 +415,7 @@ static struct ctl_table kern_table[] = { .data = core_pattern, .maxlen = CORENAME_MAX_SIZE, .mode = 0644, - .proc_handler = proc_dostring, + .proc_handler = proc_dostring_coredump, }, { .procname = "core_pipe_limit", @@ -1498,7 +1503,7 @@ static struct ctl_table fs_table[] = { .data = &suid_dumpable, .maxlen = sizeof(int), .mode = 0644, - .proc_handler = proc_dointvec_minmax, + .proc_handler = proc_dointvec_minmax_coredump, .extra1 = &zero, .extra2 = &two, }, @@ -2009,6 +2014,34 @@ int proc_dointvec_minmax(struct ctl_table *table, int write, do_proc_dointvec_minmax_conv, ¶m); } +static void validate_coredump_safety(void) +{ + if (suid_dumpable == SUID_DUMPABLE_SAFE && + core_pattern[0] != '/' && core_pattern[0] != '|') { + printk(KERN_WARNING "Unsafe core_pattern used with "\ + "suid_dumpable=2. Pipe handler or fully qualified "\ + "core dump path required.\n"); + } +} + +static int proc_dointvec_minmax_coredump(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + int error = proc_dointvec_minmax(table, write, buffer, lenp, ppos); + if (!error) + validate_coredump_safety(); + return error; +} + +static int proc_dostring_coredump(struct ctl_table *table, int write, + void __user *buffer, size_t *lenp, loff_t *ppos) +{ + int error = proc_dostring(table, write, buffer, lenp, ppos); + if (!error) + validate_coredump_safety(); + return error; +} + static int __do_proc_doulongvec_minmax(void *data, struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos, |