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Subject[PATCH] fs/xattr.c:getxattr(): improve handling of allocation failures
Date
This allocation can be as large as 64k.

- Add __GFP_NOWARN so the falied kmalloc() is silent

- Fall back to vmalloc() if the kmalloc() failed

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
fs/xattr.c | 16 ++++++++++++----
1 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/fs/xattr.c b/fs/xattr.c
index 1d7ac37..4d45b71 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -427,6 +427,7 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,
{
ssize_t error;
void *kvalue = NULL;
+ void *vvalue = NULL;
char kname[XATTR_NAME_MAX + 1];

error = strncpy_from_user(kname, name, sizeof(kname));
@@ -438,9 +439,13 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,
if (size) {
if (size > XATTR_SIZE_MAX)
size = XATTR_SIZE_MAX;
- kvalue = kzalloc(size, GFP_KERNEL);
- if (!kvalue)
- return -ENOMEM;
+ kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
+ if (!kvalue) {
+ vvalue = vmalloc(size);
+ if (!vvalue)
+ return -ENOMEM;
+ kvalue = vvalue;
+ }
}

error = vfs_getxattr(d, kname, kvalue, size);
@@ -452,7 +457,10 @@ getxattr(struct dentry *d, const char __user *name, void __user *value,
than XATTR_SIZE_MAX bytes. Not possible. */
error = -E2BIG;
}
- kfree(kvalue);
+ if (vvalue)
+ vfree(vvalue);
+ else
+ kfree(kvalue);
return error;
}

--
1.7.8.6


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