Commit d4b0bcf3 authored by David Teigland's avatar David Teigland

dlm: check the write size from user

Return EINVAL from write if the size is larger than
allowed.  Do this before allocating kernel memory for
the bogus size, which could lead to OOM.
Reported-by: default avatarSasha Levin <levinsasha928@gmail.com>
Tested-by: default avatarJana Saout <jana@saout.de>
Signed-off-by: default avatarDavid Teigland <teigland@redhat.com>
parent 6edacf05
...@@ -503,11 +503,11 @@ static ssize_t device_write(struct file *file, const char __user *buf, ...@@ -503,11 +503,11 @@ static ssize_t device_write(struct file *file, const char __user *buf,
#endif #endif
return -EINVAL; return -EINVAL;
#ifdef CONFIG_COMPAT /*
if (count > sizeof(struct dlm_write_request32) + DLM_RESNAME_MAXLEN) * can't compare against COMPAT/dlm_write_request32 because
#else * we don't yet know if is64bit is zero
*/
if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN) if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
#endif
return -EINVAL; return -EINVAL;
kbuf = kzalloc(count + 1, GFP_NOFS); kbuf = kzalloc(count + 1, GFP_NOFS);
......
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