diff options
Diffstat (limited to 'arch/powerpc/kernel/rtas.c')
| -rw-r--r-- | arch/powerpc/kernel/rtas.c | 214 |
1 files changed, 197 insertions, 17 deletions
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index 95d1264ba795..2646dd54eb0b 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -54,10 +54,10 @@ struct rtas_t rtas = { EXPORT_SYMBOL(rtas); DEFINE_SPINLOCK(rtas_data_buf_lock); -EXPORT_SYMBOL(rtas_data_buf_lock); +EXPORT_SYMBOL_GPL(rtas_data_buf_lock); -char rtas_data_buf[RTAS_DATA_BUF_SIZE] __cacheline_aligned; -EXPORT_SYMBOL(rtas_data_buf); +char rtas_data_buf[RTAS_DATA_BUF_SIZE] __aligned(SZ_4K); +EXPORT_SYMBOL_GPL(rtas_data_buf); unsigned long rtas_rmo_buf; @@ -66,7 +66,7 @@ unsigned long rtas_rmo_buf; * This is done like this so rtas_flash can be a module. */ void (*rtas_flash_term_hook)(int); -EXPORT_SYMBOL(rtas_flash_term_hook); +EXPORT_SYMBOL_GPL(rtas_flash_term_hook); /* RTAS use home made raw locking instead of spin_lock_irqsave * because those can be called from within really nasty contexts @@ -314,7 +314,7 @@ void rtas_progress(char *s, unsigned short hex) spin_unlock(&progress_lock); } -EXPORT_SYMBOL(rtas_progress); /* needed by rtas_flash module */ +EXPORT_SYMBOL_GPL(rtas_progress); /* needed by rtas_flash module */ int rtas_token(const char *service) { @@ -324,7 +324,7 @@ int rtas_token(const char *service) tokp = of_get_property(rtas.dev, service, NULL); return tokp ? be32_to_cpu(*tokp) : RTAS_UNKNOWN_SERVICE; } -EXPORT_SYMBOL(rtas_token); +EXPORT_SYMBOL_GPL(rtas_token); int rtas_service_present(const char *service) { @@ -401,7 +401,7 @@ static char *__fetch_rtas_last_error(char *altbuf) buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC); } if (buf) - memcpy(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX); + memmove(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX); } return buf; @@ -484,7 +484,7 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...) } return ret; } -EXPORT_SYMBOL(rtas_call); +EXPORT_SYMBOL_GPL(rtas_call); /* For RTAS_BUSY (-2), delay for 1 millisecond. For an extended busy status * code of 990n, perform the hinted delay of 10^n (last digit) milliseconds. @@ -519,7 +519,7 @@ unsigned int rtas_busy_delay(int status) return ms; } -EXPORT_SYMBOL(rtas_busy_delay); +EXPORT_SYMBOL_GPL(rtas_busy_delay); static int rtas_error_rc(int rtas_rc) { @@ -565,7 +565,7 @@ int rtas_get_power_level(int powerdomain, int *level) return rtas_error_rc(rc); return rc; } -EXPORT_SYMBOL(rtas_get_power_level); +EXPORT_SYMBOL_GPL(rtas_get_power_level); int rtas_set_power_level(int powerdomain, int level, int *setlevel) { @@ -583,7 +583,7 @@ int rtas_set_power_level(int powerdomain, int level, int *setlevel) return rtas_error_rc(rc); return rc; } -EXPORT_SYMBOL(rtas_set_power_level); +EXPORT_SYMBOL_GPL(rtas_set_power_level); int rtas_get_sensor(int sensor, int index, int *state) { @@ -601,7 +601,7 @@ int rtas_get_sensor(int sensor, int index, int *state) return rtas_error_rc(rc); return rc; } -EXPORT_SYMBOL(rtas_get_sensor); +EXPORT_SYMBOL_GPL(rtas_get_sensor); int rtas_get_sensor_fast(int sensor, int index, int *state) { @@ -662,7 +662,7 @@ int rtas_set_indicator(int indicator, int index, int new_value) return rtas_error_rc(rc); return rc; } -EXPORT_SYMBOL(rtas_set_indicator); +EXPORT_SYMBOL_GPL(rtas_set_indicator); /* * Ignoring RTAS extended delay @@ -717,6 +717,7 @@ void __noreturn rtas_halt(void) /* Must be in the RMO region, so we place it here */ static char rtas_os_term_buf[2048]; +static s32 ibm_os_term_token = RTAS_UNKNOWN_SERVICE; void rtas_os_term(char *str) { @@ -728,16 +729,20 @@ void rtas_os_term(char *str) * this property may terminate the partition which we want to avoid * since it interferes with panic_timeout. */ - if (RTAS_UNKNOWN_SERVICE == rtas_token("ibm,os-term") || - RTAS_UNKNOWN_SERVICE == rtas_token("ibm,extended-os-term")) + if (ibm_os_term_token == RTAS_UNKNOWN_SERVICE) return; snprintf(rtas_os_term_buf, 2048, "OS panic: %s", str); + /* + * Keep calling as long as RTAS returns a "try again" status, + * but don't use rtas_busy_delay(), which potentially + * schedules. + */ do { - status = rtas_call(rtas_token("ibm,os-term"), 1, 1, NULL, + status = rtas_call(ibm_os_term_token, 1, 1, NULL, __pa(rtas_os_term_buf)); - } while (rtas_busy_delay(status)); + } while (rtas_busy_delay_time(status)); if (status != 0) printk(KERN_EMERG "ibm,os-term call failed %d\n", status); @@ -1057,6 +1062,156 @@ struct pseries_errorlog *get_pseries_errorlog(struct rtas_error_log *log, return NULL; } +#ifdef CONFIG_PPC_RTAS_FILTER + +/* + * The sys_rtas syscall, as originally designed, allows root to pass + * arbitrary physical addresses to RTAS calls. A number of RTAS calls + * can be abused to write to arbitrary memory and do other things that + * are potentially harmful to system integrity, and thus should only + * be used inside the kernel and not exposed to userspace. + * + * All known legitimate users of the sys_rtas syscall will only ever + * pass addresses that fall within the RMO buffer, and use a known + * subset of RTAS calls. + * + * Accordingly, we filter RTAS requests to check that the call is + * permitted, and that provided pointers fall within the RMO buffer. + * The rtas_filters list contains an entry for each permitted call, + * with the indexes of the parameters which are expected to contain + * addresses and sizes of buffers allocated inside the RMO buffer. + */ +struct rtas_filter { + const char *name; + int token; + /* Indexes into the args buffer, -1 if not used */ + int buf_idx1; + int size_idx1; + int buf_idx2; + int size_idx2; + + int fixed_size; +}; + +static struct rtas_filter rtas_filters[] __ro_after_init = { + { "ibm,activate-firmware", -1, -1, -1, -1, -1 }, + { "ibm,configure-connector", -1, 0, -1, 1, -1, 4096 }, /* Special cased */ + { "display-character", -1, -1, -1, -1, -1 }, + { "ibm,display-message", -1, 0, -1, -1, -1 }, + { "ibm,errinjct", -1, 2, -1, -1, -1, 1024 }, + { "ibm,close-errinjct", -1, -1, -1, -1, -1 }, + { "ibm,open-errinjct", -1, -1, -1, -1, -1 }, + { "ibm,get-config-addr-info2", -1, -1, -1, -1, -1 }, + { "ibm,get-dynamic-sensor-state", -1, 1, -1, -1, -1 }, + { "ibm,get-indices", -1, 2, 3, -1, -1 }, + { "get-power-level", -1, -1, -1, -1, -1 }, + { "get-sensor-state", -1, -1, -1, -1, -1 }, + { "ibm,get-system-parameter", -1, 1, 2, -1, -1 }, + { "get-time-of-day", -1, -1, -1, -1, -1 }, + { "ibm,get-vpd", -1, 0, -1, 1, 2 }, + { "ibm,lpar-perftools", -1, 2, 3, -1, -1 }, + { "ibm,platform-dump", -1, 4, 5, -1, -1 }, /* Special cased */ + { "ibm,read-slot-reset-state", -1, -1, -1, -1, -1 }, + { "ibm,scan-log-dump", -1, 0, 1, -1, -1 }, + { "ibm,set-dynamic-indicator", -1, 2, -1, -1, -1 }, + { "ibm,set-eeh-option", -1, -1, -1, -1, -1 }, + { "set-indicator", -1, -1, -1, -1, -1 }, + { "set-power-level", -1, -1, -1, -1, -1 }, + { "set-time-for-power-on", -1, -1, -1, -1, -1 }, + { "ibm,set-system-parameter", -1, 1, -1, -1, -1 }, + { "set-time-of-day", -1, -1, -1, -1, -1 }, + { "ibm,suspend-me", -1, -1, -1, -1, -1 }, + { "ibm,update-nodes", -1, 0, -1, -1, -1, 4096 }, + { "ibm,update-properties", -1, 0, -1, -1, -1, 4096 }, + { "ibm,physical-attestation", -1, 0, 1, -1, -1 }, +}; + +static bool in_rmo_buf(u32 base, u32 end) +{ + return base >= rtas_rmo_buf && + base < (rtas_rmo_buf + RTAS_RMOBUF_MAX) && + base <= end && + end >= rtas_rmo_buf && + end < (rtas_rmo_buf + RTAS_RMOBUF_MAX); +} + +static bool block_rtas_call(int token, int nargs, + struct rtas_args *args) +{ + int i; + + for (i = 0; i < ARRAY_SIZE(rtas_filters); i++) { + struct rtas_filter *f = &rtas_filters[i]; + u32 base, size, end; + + if (token != f->token) + continue; + + if (f->buf_idx1 != -1) { + base = be32_to_cpu(args->args[f->buf_idx1]); + if (f->size_idx1 != -1) + size = be32_to_cpu(args->args[f->size_idx1]); + else if (f->fixed_size) + size = f->fixed_size; + else + size = 1; + + end = base + size - 1; + + /* + * Special case for ibm,platform-dump - NULL buffer + * address is used to indicate end of dump processing + */ + if (!strcmp(f->name, "ibm,platform-dump") && + base == 0) + return false; + + if (!in_rmo_buf(base, end)) + goto err; + } + + if (f->buf_idx2 != -1) { + base = be32_to_cpu(args->args[f->buf_idx2]); + if (f->size_idx2 != -1) + size = be32_to_cpu(args->args[f->size_idx2]); + else if (f->fixed_size) + size = f->fixed_size; + else + size = 1; + end = base + size - 1; + + /* + * Special case for ibm,configure-connector where the + * address can be 0 + */ + if (!strcmp(f->name, "ibm,configure-connector") && + base == 0) + return false; + + if (!in_rmo_buf(base, end)) + goto err; + } + + return false; + } + +err: + pr_err_ratelimited("sys_rtas: RTAS call blocked - exploit attempt?\n"); + pr_err_ratelimited("sys_rtas: token=0x%x, nargs=%d (called by %s)\n", + token, nargs, current->comm); + return true; +} + +#else + +static bool block_rtas_call(int token, int nargs, + struct rtas_args *args) +{ + return false; +} + +#endif /* CONFIG_PPC_RTAS_FILTER */ + /* We assume to be passed big endian arguments */ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs) { @@ -1094,6 +1249,9 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs) args.rets = &args.args[nargs]; memset(args.rets, 0, nret * sizeof(rtas_arg_t)); + if (block_rtas_call(token, nargs, &args)) + return -EINVAL; + /* Need to handle ibm,suspend_me call specially */ if (token == ibm_suspend_me_token) { @@ -1155,6 +1313,9 @@ void __init rtas_initialize(void) unsigned long rtas_region = RTAS_INSTANTIATE_MAX; u32 base, size, entry; int no_base, no_size, no_entry; +#ifdef CONFIG_PPC_RTAS_FILTER + int i; +#endif /* Get RTAS dev node and fill up our "rtas" structure with infos * about it. @@ -1176,6 +1337,13 @@ void __init rtas_initialize(void) no_entry = of_property_read_u32(rtas.dev, "linux,rtas-entry", &entry); rtas.entry = no_entry ? rtas.base : entry; + /* + * Discover these now to avoid device tree lookups in the + * panic path. + */ + if (of_property_read_bool(rtas.dev, "ibm,extended-os-term")) + ibm_os_term_token = rtas_token("ibm,os-term"); + /* If RTAS was found, allocate the RMO buffer for it and look for * the stop-self token if any */ @@ -1190,6 +1358,12 @@ void __init rtas_initialize(void) #ifdef CONFIG_RTAS_ERROR_LOGGING rtas_last_error_token = rtas_token("rtas-last-error"); #endif + +#ifdef CONFIG_PPC_RTAS_FILTER + for (i = 0; i < ARRAY_SIZE(rtas_filters); i++) { + rtas_filters[i].token = rtas_token(rtas_filters[i].name); + } +#endif } int __init early_init_dt_scan_rtas(unsigned long node, @@ -1204,6 +1378,12 @@ int __init early_init_dt_scan_rtas(unsigned long node, entryp = of_get_flat_dt_prop(node, "linux,rtas-entry", NULL); sizep = of_get_flat_dt_prop(node, "rtas-size", NULL); +#ifdef CONFIG_PPC64 + /* need this feature to decide the crashkernel offset */ + if (of_get_flat_dt_prop(node, "ibm,hypertas-functions", NULL)) + powerpc_firmware_features |= FW_FEATURE_LPAR; +#endif + if (basep && entryp && sizep) { rtas.base = *basep; rtas.entry = *entryp; |