diff --git a/security/apparmor/include/path.h b/security/apparmor/include/path.h index 73560f258784fc3256878f953ad8d194c086106d..0444fdde3918905dded243442a9743a7497c183b 100644 --- a/security/apparmor/include/path.h +++ b/security/apparmor/include/path.h @@ -29,4 +29,57 @@ enum path_flags { int aa_path_name(const struct path *path, int flags, char **buffer, const char **name, const char **info); +#define MAX_PATH_BUFFERS 2 + +/* Per cpu buffers used during mediation */ +/* preallocated buffers to use during path lookups */ +struct aa_buffers { + char *buf[MAX_PATH_BUFFERS]; +}; + +#include +#include + +DECLARE_PER_CPU(struct aa_buffers, aa_buffers); + +#define COUNT_ARGS(X...) COUNT_ARGS_HELPER(, ##X, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0) +#define COUNT_ARGS_HELPER(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, n, X...) n +#define CONCAT(X, Y) X ## Y +#define CONCAT_AFTER(X, Y) CONCAT(X, Y) + +#define ASSIGN(FN, X, N) ((X) = FN(N)) +#define EVAL1(FN, X) ASSIGN(FN, X, 0) /*X = FN(0)*/ +#define EVAL2(FN, X, Y...) do { ASSIGN(FN, X, 1); EVAL1(FN, Y); } while (0) +#define EVAL(FN, X...) CONCAT_AFTER(EVAL, COUNT_ARGS(X))(FN, X) + +#define for_each_cpu_buffer(I) for ((I) = 0; (I) < MAX_PATH_BUFFERS; (I)++) + +#ifdef CONFIG_DEBUG_PREEMPT +#define AA_BUG_PREEMPT_ENABLED(X) AA_BUG(preempt_count() <= 0, X) +#else +#define AA_BUG_PREEMPT_ENABLED(X) /* nop */ +#endif + +#define __get_buffer(N) ({ \ + struct aa_buffers *__cpu_var; \ + AA_BUG_PREEMPT_ENABLED("__get_buffer without preempt disabled"); \ + __cpu_var = this_cpu_ptr(&aa_buffers); \ + __cpu_var->buf[(N)]; }) + +#define __get_buffers(X...) EVAL(__get_buffer, X) + +#define __put_buffers(X, Y...) ((void)&(X)) + +#define get_buffers(X...) \ +do { \ + preempt_disable(); \ + __get_buffers(X); \ +} while (0) + +#define put_buffers(X, Y...) \ +do { \ + __put_buffers(X, Y); \ + preempt_enable(); \ +} while (0) + #endif /* __AA_PATH_H */ diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 8a887c392fdb4e8879945a9a8f7768fbac065e0b..c249ea0e6328ce5b4be2812c9b2677f0056d0107 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -41,6 +41,9 @@ /* Flag indicating whether initialization completed */ int apparmor_initialized __initdata; +DEFINE_PER_CPU(struct aa_buffers, aa_buffers); + + /* * LSM hook functions */ @@ -868,6 +871,43 @@ static int __init set_init_ctx(void) return 0; } +static void destroy_buffers(void) +{ + u32 i, j; + + for_each_possible_cpu(i) { + for_each_cpu_buffer(j) { + kfree(per_cpu(aa_buffers, i).buf[j]); + per_cpu(aa_buffers, i).buf[j] = NULL; + } + } +} + +static int __init alloc_buffers(void) +{ + u32 i, j; + + for_each_possible_cpu(i) { + for_each_cpu_buffer(j) { + char *buffer; + + if (cpu_to_node(i) > num_online_nodes()) + /* fallback to kmalloc for offline nodes */ + buffer = kmalloc(aa_g_path_max, GFP_KERNEL); + else + buffer = kmalloc_node(aa_g_path_max, GFP_KERNEL, + cpu_to_node(i)); + if (!buffer) { + destroy_buffers(); + return -ENOMEM; + } + per_cpu(aa_buffers, i).buf[j] = buffer; + } + } + + return 0; +} + #ifdef CONFIG_SYSCTL static int apparmor_dointvec(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) @@ -937,11 +977,17 @@ static int __init apparmor_init(void) } + error = alloc_buffers(); + if (error) { + AA_ERROR("Unable to allocate work buffers\n"); + goto buffers_out; + } + error = set_init_ctx(); if (error) { AA_ERROR("Failed to set context on init task\n"); aa_free_root_ns(); - goto alloc_out; + goto buffers_out; } security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks)); @@ -956,6 +1002,9 @@ static int __init apparmor_init(void) return error; +buffers_out: + destroy_buffers(); + alloc_out: aa_destroy_aafs(); aa_teardown_dfa_engine();