linux/net/dccp/ccid.c

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/*
* net/dccp/ccid.c
*
* An implementation of the DCCP protocol
* Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* CCID infrastructure
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include "ccid.h"
#include "ccids/lib/tfrc.h"
static struct ccid_operations *ccids[] = {
&ccid2_ops,
#ifdef CONFIG_IP_DCCP_CCID3
&ccid3_ops,
#endif
};
static struct ccid_operations *ccid_by_number(const u8 id)
{
int i;
for (i = 0; i < ARRAY_SIZE(ccids); i++)
if (ccids[i]->ccid_id == id)
return ccids[i];
return NULL;
}
/* check that up to @array_len members in @ccid_array are supported */
bool ccid_support_check(u8 const *ccid_array, u8 array_len)
{
while (array_len > 0)
if (ccid_by_number(ccid_array[--array_len]) == NULL)
return false;
return true;
}
/**
* ccid_get_builtin_ccids - Populate a list of built-in CCIDs
* @ccid_array: pointer to copy into
* @array_len: value to return length into
* This function allocates memory - caller must see that it is freed after use.
*/
int ccid_get_builtin_ccids(u8 **ccid_array, u8 *array_len)
{
*ccid_array = kmalloc(ARRAY_SIZE(ccids), gfp_any());
if (*ccid_array == NULL)
return -ENOBUFS;
for (*array_len = 0; *array_len < ARRAY_SIZE(ccids); *array_len += 1)
(*ccid_array)[*array_len] = ccids[*array_len]->ccid_id;
return 0;
}
int ccid_getsockopt_builtin_ccids(struct sock *sk, int len,
char __user *optval, int __user *optlen)
{
u8 *ccid_array, array_len;
int err = 0;
if (ccid_get_builtin_ccids(&ccid_array, &array_len))
return -ENOBUFS;
if (put_user(array_len, optlen))
err = -EFAULT;
else if (len > 0 && copy_to_user(optval, ccid_array,
len > array_len ? array_len : len))
err = -EFAULT;
kfree(ccid_array);
return err;
}
dccp: fix dccp rmmod when kernel configured to use slub Hey all- I was tinkering with dccp recently and noticed that I BUG halted the kernel when I rmmod-ed the dccp module. The bug halt occured because the page that I passed to kfree failed the PageCompound and PageSlab test in the slub implementation of kfree. I tracked the problem down to the following set of events: 1) dccp, unlike all other uses of kmem_cache_create, allocates a string dynamically when registering a slab cache. This allocated string is freed when the cache is destroyed. 2) Normally, (1) is not an issue, but when Slub is in use, it is possible that caches are 'merged'. This process causes multiple caches of simmilar configuration to use the same cache data structure. When this happens, the new name of the cache is effectively dropped. 3) (2) results in kmem_cache_name returning an ambigous value (i.e. ccid_kmem_cache_destroy, which uses this fuction to retrieve the name pointer for freeing), is no longer guaranteed that the string it assigned is what is returned. 4) If such merge event occurs, ccid_kmem_cache_destroy frees the wrong pointer, which trips over the BUG in the slub implementation of kfree (since its likely not a slab allocation, but rather a pointer into the static string table section. So, what to do about this. At first blush this is pretty clearly a leak in the information that slub owns, and as such a slub bug. Unfortunately, theres no really good way to fix it, without exposing slub specific implementation details to the generic slab interface. Also, even if we could fix this in slub cleanly, I think the RCU free option would force us to do lots of string duplication, not only in slub, but in every slab allocator. As such, I'd like to propose this solution. Basically, I just move the storage for the kmem cache name to the ccid_operations structure. In so doing, we don't have to do the kstrdup or kfree when we allocate/free the various caches for dccp, and so we avoid the problem, by storing names with static memory, rather than heap, the way all other calls to kmem_cache_create do. I've tested this out myself here, and it solves the problem quite well. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-17 17:16:12 +00:00
static struct kmem_cache *ccid_kmem_cache_create(int obj_size, char *slab_name_fmt, const char *fmt,...)
{
struct kmem_cache *slab;
va_list args;
va_start(args, fmt);
vsnprintf(slab_name_fmt, CCID_SLAB_NAME_LENGTH, fmt, args);
va_end(args);
dccp: fix dccp rmmod when kernel configured to use slub Hey all- I was tinkering with dccp recently and noticed that I BUG halted the kernel when I rmmod-ed the dccp module. The bug halt occured because the page that I passed to kfree failed the PageCompound and PageSlab test in the slub implementation of kfree. I tracked the problem down to the following set of events: 1) dccp, unlike all other uses of kmem_cache_create, allocates a string dynamically when registering a slab cache. This allocated string is freed when the cache is destroyed. 2) Normally, (1) is not an issue, but when Slub is in use, it is possible that caches are 'merged'. This process causes multiple caches of simmilar configuration to use the same cache data structure. When this happens, the new name of the cache is effectively dropped. 3) (2) results in kmem_cache_name returning an ambigous value (i.e. ccid_kmem_cache_destroy, which uses this fuction to retrieve the name pointer for freeing), is no longer guaranteed that the string it assigned is what is returned. 4) If such merge event occurs, ccid_kmem_cache_destroy frees the wrong pointer, which trips over the BUG in the slub implementation of kfree (since its likely not a slab allocation, but rather a pointer into the static string table section. So, what to do about this. At first blush this is pretty clearly a leak in the information that slub owns, and as such a slub bug. Unfortunately, theres no really good way to fix it, without exposing slub specific implementation details to the generic slab interface. Also, even if we could fix this in slub cleanly, I think the RCU free option would force us to do lots of string duplication, not only in slub, but in every slab allocator. As such, I'd like to propose this solution. Basically, I just move the storage for the kmem cache name to the ccid_operations structure. In so doing, we don't have to do the kstrdup or kfree when we allocate/free the various caches for dccp, and so we avoid the problem, by storing names with static memory, rather than heap, the way all other calls to kmem_cache_create do. I've tested this out myself here, and it solves the problem quite well. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-17 17:16:12 +00:00
slab = kmem_cache_create(slab_name_fmt, sizeof(struct ccid) + obj_size, 0,
SLAB_HWCACHE_ALIGN, NULL);
return slab;
}
static void ccid_kmem_cache_destroy(struct kmem_cache *slab)
{
dccp: fix dccp rmmod when kernel configured to use slub Hey all- I was tinkering with dccp recently and noticed that I BUG halted the kernel when I rmmod-ed the dccp module. The bug halt occured because the page that I passed to kfree failed the PageCompound and PageSlab test in the slub implementation of kfree. I tracked the problem down to the following set of events: 1) dccp, unlike all other uses of kmem_cache_create, allocates a string dynamically when registering a slab cache. This allocated string is freed when the cache is destroyed. 2) Normally, (1) is not an issue, but when Slub is in use, it is possible that caches are 'merged'. This process causes multiple caches of simmilar configuration to use the same cache data structure. When this happens, the new name of the cache is effectively dropped. 3) (2) results in kmem_cache_name returning an ambigous value (i.e. ccid_kmem_cache_destroy, which uses this fuction to retrieve the name pointer for freeing), is no longer guaranteed that the string it assigned is what is returned. 4) If such merge event occurs, ccid_kmem_cache_destroy frees the wrong pointer, which trips over the BUG in the slub implementation of kfree (since its likely not a slab allocation, but rather a pointer into the static string table section. So, what to do about this. At first blush this is pretty clearly a leak in the information that slub owns, and as such a slub bug. Unfortunately, theres no really good way to fix it, without exposing slub specific implementation details to the generic slab interface. Also, even if we could fix this in slub cleanly, I think the RCU free option would force us to do lots of string duplication, not only in slub, but in every slab allocator. As such, I'd like to propose this solution. Basically, I just move the storage for the kmem cache name to the ccid_operations structure. In so doing, we don't have to do the kstrdup or kfree when we allocate/free the various caches for dccp, and so we avoid the problem, by storing names with static memory, rather than heap, the way all other calls to kmem_cache_create do. I've tested this out myself here, and it solves the problem quite well. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-17 17:16:12 +00:00
if (slab != NULL)
kmem_cache_destroy(slab);
}
static int ccid_activate(struct ccid_operations *ccid_ops)
{
int err = -ENOBUFS;
ccid_ops->ccid_hc_rx_slab =
ccid_kmem_cache_create(ccid_ops->ccid_hc_rx_obj_size,
dccp: fix dccp rmmod when kernel configured to use slub Hey all- I was tinkering with dccp recently and noticed that I BUG halted the kernel when I rmmod-ed the dccp module. The bug halt occured because the page that I passed to kfree failed the PageCompound and PageSlab test in the slub implementation of kfree. I tracked the problem down to the following set of events: 1) dccp, unlike all other uses of kmem_cache_create, allocates a string dynamically when registering a slab cache. This allocated string is freed when the cache is destroyed. 2) Normally, (1) is not an issue, but when Slub is in use, it is possible that caches are 'merged'. This process causes multiple caches of simmilar configuration to use the same cache data structure. When this happens, the new name of the cache is effectively dropped. 3) (2) results in kmem_cache_name returning an ambigous value (i.e. ccid_kmem_cache_destroy, which uses this fuction to retrieve the name pointer for freeing), is no longer guaranteed that the string it assigned is what is returned. 4) If such merge event occurs, ccid_kmem_cache_destroy frees the wrong pointer, which trips over the BUG in the slub implementation of kfree (since its likely not a slab allocation, but rather a pointer into the static string table section. So, what to do about this. At first blush this is pretty clearly a leak in the information that slub owns, and as such a slub bug. Unfortunately, theres no really good way to fix it, without exposing slub specific implementation details to the generic slab interface. Also, even if we could fix this in slub cleanly, I think the RCU free option would force us to do lots of string duplication, not only in slub, but in every slab allocator. As such, I'd like to propose this solution. Basically, I just move the storage for the kmem cache name to the ccid_operations structure. In so doing, we don't have to do the kstrdup or kfree when we allocate/free the various caches for dccp, and so we avoid the problem, by storing names with static memory, rather than heap, the way all other calls to kmem_cache_create do. I've tested this out myself here, and it solves the problem quite well. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-17 17:16:12 +00:00
ccid_ops->ccid_hc_rx_slab_name,
"ccid%u_hc_rx_sock",
ccid_ops->ccid_id);
if (ccid_ops->ccid_hc_rx_slab == NULL)
goto out;
ccid_ops->ccid_hc_tx_slab =
ccid_kmem_cache_create(ccid_ops->ccid_hc_tx_obj_size,
dccp: fix dccp rmmod when kernel configured to use slub Hey all- I was tinkering with dccp recently and noticed that I BUG halted the kernel when I rmmod-ed the dccp module. The bug halt occured because the page that I passed to kfree failed the PageCompound and PageSlab test in the slub implementation of kfree. I tracked the problem down to the following set of events: 1) dccp, unlike all other uses of kmem_cache_create, allocates a string dynamically when registering a slab cache. This allocated string is freed when the cache is destroyed. 2) Normally, (1) is not an issue, but when Slub is in use, it is possible that caches are 'merged'. This process causes multiple caches of simmilar configuration to use the same cache data structure. When this happens, the new name of the cache is effectively dropped. 3) (2) results in kmem_cache_name returning an ambigous value (i.e. ccid_kmem_cache_destroy, which uses this fuction to retrieve the name pointer for freeing), is no longer guaranteed that the string it assigned is what is returned. 4) If such merge event occurs, ccid_kmem_cache_destroy frees the wrong pointer, which trips over the BUG in the slub implementation of kfree (since its likely not a slab allocation, but rather a pointer into the static string table section. So, what to do about this. At first blush this is pretty clearly a leak in the information that slub owns, and as such a slub bug. Unfortunately, theres no really good way to fix it, without exposing slub specific implementation details to the generic slab interface. Also, even if we could fix this in slub cleanly, I think the RCU free option would force us to do lots of string duplication, not only in slub, but in every slab allocator. As such, I'd like to propose this solution. Basically, I just move the storage for the kmem cache name to the ccid_operations structure. In so doing, we don't have to do the kstrdup or kfree when we allocate/free the various caches for dccp, and so we avoid the problem, by storing names with static memory, rather than heap, the way all other calls to kmem_cache_create do. I've tested this out myself here, and it solves the problem quite well. Signed-off-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-01-17 17:16:12 +00:00
ccid_ops->ccid_hc_tx_slab_name,
"ccid%u_hc_tx_sock",
ccid_ops->ccid_id);
if (ccid_ops->ccid_hc_tx_slab == NULL)
goto out_free_rx_slab;
pr_info("CCID: Activated CCID %d (%s)\n",
ccid_ops->ccid_id, ccid_ops->ccid_name);
err = 0;
out:
return err;
out_free_rx_slab:
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
ccid_ops->ccid_hc_rx_slab = NULL;
goto out;
}
static void ccid_deactivate(struct ccid_operations *ccid_ops)
{
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_tx_slab);
ccid_ops->ccid_hc_tx_slab = NULL;
ccid_kmem_cache_destroy(ccid_ops->ccid_hc_rx_slab);
ccid_ops->ccid_hc_rx_slab = NULL;
pr_info("CCID: Deactivated CCID %d (%s)\n",
ccid_ops->ccid_id, ccid_ops->ccid_name);
}
struct ccid *ccid_new(const u8 id, struct sock *sk, bool rx)
{
struct ccid_operations *ccid_ops = ccid_by_number(id);
struct ccid *ccid = NULL;
if (ccid_ops == NULL)
goto out;
ccid = kmem_cache_alloc(rx ? ccid_ops->ccid_hc_rx_slab :
ccid_ops->ccid_hc_tx_slab, gfp_any());
if (ccid == NULL)
goto out;
ccid->ccid_ops = ccid_ops;
if (rx) {
memset(ccid + 1, 0, ccid_ops->ccid_hc_rx_obj_size);
if (ccid->ccid_ops->ccid_hc_rx_init != NULL &&
ccid->ccid_ops->ccid_hc_rx_init(ccid, sk) != 0)
goto out_free_ccid;
} else {
memset(ccid + 1, 0, ccid_ops->ccid_hc_tx_obj_size);
if (ccid->ccid_ops->ccid_hc_tx_init != NULL &&
ccid->ccid_ops->ccid_hc_tx_init(ccid, sk) != 0)
goto out_free_ccid;
}
out:
return ccid;
out_free_ccid:
kmem_cache_free(rx ? ccid_ops->ccid_hc_rx_slab :
ccid_ops->ccid_hc_tx_slab, ccid);
ccid = NULL;
goto out;
}
void ccid_hc_rx_delete(struct ccid *ccid, struct sock *sk)
{
if (ccid != NULL) {
if (ccid->ccid_ops->ccid_hc_rx_exit != NULL)
ccid->ccid_ops->ccid_hc_rx_exit(sk);
kmem_cache_free(ccid->ccid_ops->ccid_hc_rx_slab, ccid);
}
}
void ccid_hc_tx_delete(struct ccid *ccid, struct sock *sk)
{
if (ccid != NULL) {
if (ccid->ccid_ops->ccid_hc_tx_exit != NULL)
ccid->ccid_ops->ccid_hc_tx_exit(sk);
kmem_cache_free(ccid->ccid_ops->ccid_hc_tx_slab, ccid);
}
}
int __init ccid_initialize_builtins(void)
{
int i, err = tfrc_lib_init();
if (err)
return err;
for (i = 0; i < ARRAY_SIZE(ccids); i++) {
err = ccid_activate(ccids[i]);
if (err)
goto unwind_registrations;
}
return 0;
unwind_registrations:
while(--i >= 0)
ccid_deactivate(ccids[i]);
tfrc_lib_exit();
return err;
}
void ccid_cleanup_builtins(void)
{
int i;
for (i = 0; i < ARRAY_SIZE(ccids); i++)
ccid_deactivate(ccids[i]);
tfrc_lib_exit();
}