Revision f818a73674c5d197f66b636a46d7d578d7258129 authored by Sage Weil on 12 May 2010, 03:56:31 UTC, committed by Sage Weil on 12 May 2010, 03:56:31 UTC
The iterate_session_caps helper traverses the session caps list and tries to grab an inode reference. However, the __ceph_remove_cap was clearing the inode backpointer _before_ removing itself from the session list, causing a null pointer dereference. Clear cap->ci under protection of s_cap_lock to avoid the race, and to tightly couple the list and backpointer state. Use a local flag to indicate whether we are releasing the cap, as cap->session may be modified by a racing thread in iterate_session_caps. Signed-off-by: Sage Weil <sage@newdream.net>
1 parent 45c6ceb
min_addr.c
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/security.h>
#include <linux/sysctl.h>
/* amount of vm to protect from userspace access by both DAC and the LSM*/
unsigned long mmap_min_addr;
/* amount of vm to protect from userspace using CAP_SYS_RAWIO (DAC) */
unsigned long dac_mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR;
/* amount of vm to protect from userspace using the LSM = CONFIG_LSM_MMAP_MIN_ADDR */
/*
* Update mmap_min_addr = max(dac_mmap_min_addr, CONFIG_LSM_MMAP_MIN_ADDR)
*/
static void update_mmap_min_addr(void)
{
#ifdef CONFIG_LSM_MMAP_MIN_ADDR
if (dac_mmap_min_addr > CONFIG_LSM_MMAP_MIN_ADDR)
mmap_min_addr = dac_mmap_min_addr;
else
mmap_min_addr = CONFIG_LSM_MMAP_MIN_ADDR;
#else
mmap_min_addr = dac_mmap_min_addr;
#endif
}
/*
* sysctl handler which just sets dac_mmap_min_addr = the new value and then
* calls update_mmap_min_addr() so non MAP_FIXED hints get rounded properly
*/
int mmap_min_addr_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
int ret;
if (!capable(CAP_SYS_RAWIO))
return -EPERM;
ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos);
update_mmap_min_addr();
return ret;
}
static int __init init_mmap_min_addr(void)
{
update_mmap_min_addr();
return 0;
}
pure_initcall(init_mmap_min_addr);
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