/* * security/tomoyo/memory.c * * Copyright (C) 2005-2011 NTT DATA CORPORATION */ #include #include #include "common.h" /** * tomoyo_warn_oom - Print out of memory warning message. * * @function: Function's name. */ void tomoyo_warn_oom(const char *function) { /* Reduce error messages. */ static pid_t tomoyo_last_pid; const pid_t pid = current->pid; if (tomoyo_last_pid != pid) { printk(KERN_WARNING "ERROR: Out of memory at %s.\n", function); tomoyo_last_pid = pid; } if (!tomoyo_policy_loaded) panic("MAC Initialization failed.\n"); } /* Memoy currently used by policy/audit log/query. */ unsigned int tomoyo_memory_used[TOMOYO_MAX_MEMORY_STAT]; /* Memory quota for "policy"/"audit log"/"query". */ unsigned int tomoyo_memory_quota[TOMOYO_MAX_MEMORY_STAT]; /** * tomoyo_memory_ok - Check memory quota. * * @ptr: Pointer to allocated memory. * * Returns true on success, false otherwise. * * Returns true if @ptr is not NULL and quota not exceeded, false otherwise. * * Caller holds tomoyo_policy_lock mutex. */ bool tomoyo_memory_ok(void *ptr) { if (ptr) { const size_t s = ksize(ptr); tomoyo_memory_used[TOMOYO_MEMORY_POLICY] += s; if (!tomoyo_memory_quota[TOMOYO_MEMORY_POLICY] || tomoyo_memory_used[TOMOYO_MEMORY_POLICY] <= tomoyo_memory_quota[TOMOYO_MEMORY_POLICY]) return true; tomoyo_memory_used[TOMOYO_MEMORY_POLICY] -= s; } tomoyo_warn_oom(__func__); return false; } /** * tomoyo_commit_ok - Check memory quota. * * @data: Data to copy from. * @size: Size in byte. * * Returns pointer to allocated memory on success, NULL otherwise. * @data is zero-cleared on success. * * Caller holds tomoyo_policy_lock mutex. */ void *tomoyo_commit_ok(void *data, const unsigned int size) { void *ptr = kzalloc(size, GFP_NOFS); if (tomoyo_memory_ok(ptr)) { memmove(ptr, data, size); memset(data, 0, size); return ptr; } kfree(ptr); return NULL; } /** * tomoyo_get_group - Allocate memory for "struct tomoyo_path_group"/"struct tomoyo_number_group". * * @param: Pointer to "struct tomoyo_acl_param". * @idx: Index number. * * Returns pointer to "struct tomoyo_group" on success, NULL otherwise. */ struct tomoyo_group *tomoyo_get_group(struct tomoyo_acl_param *param, const u8 idx) { struct tomoyo_group e = { }; struct tomoyo_group *group = NULL; struct list_head *list; const char *group_name = tomoyo_read_token(param); bool found = false; if (!tomoyo_correct_word(group_name) || idx >= TOMOYO_MAX_GROUP) return NULL; e.group_name = tomoyo_get_name(group_name); if (!e.group_name) return NULL; if (mutex_lock_interruptible(&tomoyo_policy_lock)) goto out; list = ¶m->ns->group_list[idx]; list_for_each_entry(group, list, head.list) { if (e.group_name != group->group_name || atomic_read(&group->head.users) == TOMOYO_GC_IN_PROGRESS) continue; atomic_inc(&group->head.users); found = true; break; } if (!found) { struct tomoyo_group *entry = tomoyo_commit_ok(&e, sizeof(e)); if (entry) { INIT_LIST_HEAD(&entry->member_list); atomic_set(&entry->head.users, 1); list_add_tail_rcu(&entry->head.list, list); group = entry; found = true; } } mutex_unlock(&tomoyo_policy_lock); out: tomoyo_put_name(e.group_name); return found ? group : NULL; } /* * tomoyo_name_list is used for holding string data used by TOMOYO. * Since same string data is likely used for multiple times (e.g. * "/lib/libc-2.5.so"), TOMOYO shares string data in the form of * "const struct tomoyo_path_info *". */ struct list_head tomoyo_name_list[TOMOYO_MAX_HASH]; /** * tomoyo_get_name - Allocate permanent memory for string data. * * @name: The string to store into the permernent memory. * * Returns pointer to "struct tomoyo_path_info" on success, NULL otherwise. */ const struct tomoyo_path_info *tomoyo_get_name(const char *name) { struct tomoyo_name *ptr; unsigned int hash; int len; struct list_head *head; if (!name) return NULL; len = strlen(name) + 1; hash = full_name_hash(NULL, (const unsigned char *) name, len - 1); head = &tomoyo_name_list[hash_long(hash, TOMOYO_HASH_BITS)]; if (mutex_lock_interruptible(&tomoyo_policy_lock)) return NULL; list_for_each_entry(ptr, head, head.list) { if (hash != ptr->entry.hash || strcmp(name, ptr->entry.name) || atomic_read(&ptr->head.users) == TOMOYO_GC_IN_PROGRESS) continue; atomic_inc(&ptr->head.users); goto out; } ptr = kzalloc(sizeof(*ptr) + len, GFP_NOFS); if (tomoyo_memory_ok(ptr)) { ptr->entry.name = ((char *) ptr) + sizeof(*ptr); memmove((char *) ptr->entry.name, name, len); atomic_set(&ptr->head.users, 1); tomoyo_fill_path_info(&ptr->entry); list_add_tail(&ptr->head.list, head); } else { kfree(ptr); ptr = NULL; } out: mutex_unlock(&tomoyo_policy_lock); return ptr ? &ptr->entry : NULL; } /* Initial namespace.*/ struct tomoyo_policy_namespace tomoyo_kernel_namespace; /** * tomoyo_mm_init - Initialize mm related code. */ void __init tomoyo_mm_init(void) { int idx; for (idx = 0; idx < TOMOYO_MAX_HASH; idx++) INIT_LIST_HEAD(&tomoyo_name_list[idx]); tomoyo_kernel_namespace.name = ""; tomoyo_init_policy_namespace(&tomoyo_kernel_namespace); tomoyo_kernel_domain.ns = &tomoyo_kernel_namespace; INIT_LIST_HEAD(&tomoyo_kernel_domain.acl_info_list); tomoyo_kernel_domain.domainname = tomoyo_get_name(""); list_add_tail_rcu(&tomoyo_kernel_domain.list, &tomoyo_domain_list); } 97e46ab3a538a565c79d26199 (diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'net/dccp/input.c')