On Thu 23-10-14 18:59:07, Dmitry Kasatkin wrote:
> On 23 October 2014 18:40, Jan Kara <j...@suse.cz> wrote:
> > On Thu 23-10-14 16:47:17, Dmitry Kasatkin wrote:
> >> ima_inode_setxattr() can be called with no value. Function does not
> >> check the length so that following command can be used to produce
> >> kernel oops: setfattr -n security.ima FOO. This patch fixes it.
> >>
> > ..
> >>
> >> Reported-by: Jan Kara <j...@suse.cz>
> >> Signed-off-by: Dmitry Kasatkin <d.kasat...@samsung.com>
> >> ---
> >> security/integrity/ima/ima_appraise.c | 2 ++
> >> 1 file changed, 2 insertions(+)
> >>
> >> diff --git a/security/integrity/ima/ima_appraise.c
> >> b/security/integrity/ima/ima_appraise.c
> >> index 5b845af..f07aacd 100644
> >> --- a/security/integrity/ima/ima_appraise.c
> >> +++ b/security/integrity/ima/ima_appraise.c
> >> @@ -378,6 +378,8 @@ int ima_inode_setxattr(struct dentry *dentry, const
> >> char *xattr_name,
> >> result = ima_protect_xattr(dentry, xattr_name, xattr_value,
> >> xattr_value_len);
> >> if (result == 1) {
> >> + if (!xattr_value_len)
> >> + return -EINVAL;
> > Wouldn't it be safer to return EINVAL whenever xattr_value_len !=
> > sizeof(evm_ima_xattr_data)?
>
> In this function we only use first byte to identify attribute type.
> sizeof(evm_ima_xattr_data) is SHA1_DIGEST_SIZE + 1.
> But IMA may use any other algorithm where digest size is different.
I see. Thanks for explanation.
Honza
> >> ima_reset_appraise_flags(dentry->d_inode,
> >> (xvalue->type == EVM_IMA_XATTR_DIGSIG) ? 1 : 0);
> >> result = 0;
> >> --
> >> 1.9.1
> >>
> > --
> > Jan Kara <j...@suse.cz>
> > SUSE Labs, CR
>
>
>
> --
> Thanks,
> Dmitry
--
Jan Kara <j...@suse.cz>
SUSE Labs, CR
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