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Code Issues Releases Activity

access() shouldn't diddle with the contents of a potentially shared

Browse Source 
credential.  Create a temporary copy of the current credential and
modify the copy.

Submitted by:	tegge
This commit is contained in:
Don Lewis 2000-09-02 12:31:55 +00:00
parent b3f212829b
commit 8577117cc8
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=65367
2 changed files with 36 additions and 16 deletions
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26
sys/kern/vfs_extattr.c
View File

@ -1593,15 +1593,25 @@ access(p, uap)
syscallarg(int) flags;
} */ *uap;
{
register struct ucred *cred = p->p_ucred;
struct ucred *cred, *tmpcred;
register struct vnode *vp;
int error, flags, t_gid, t_uid;
int error, flags;
struct nameidata nd;
t_uid = cred->cr_uid;
t_gid = cred->cr_groups[0];
cred->cr_uid = p->p_cred->p_ruid;
cred->cr_groups[0] = p->p_cred->p_rgid;
cred = p->p_ucred;
/*
* Create and modify a temporary credential instead of one that
* is potentially shared. This could also mess up socket
* buffer accounting which can run in an interrupt context.
*
* XXX - Depending on how "threads" are finally implemented, it
* may be better to explicitly pass the credential to namei()
* rather than to modify the potentially shared process structure.
*/
tmpcred = crdup(cred);
tmpcred->cr_uid = p->p_cred->p_ruid;
tmpcred->cr_groups[0] = p->p_cred->p_rgid;
p->p_ucred = tmpcred;
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | NOOBJ, UIO_USERSPACE,
SCARG(uap, path), p);
if ((error = namei(&nd)) != 0)
@ -1623,8 +1633,8 @@ access(p, uap)
NDFREE(&nd, NDF_ONLY_PNBUF);
vput(vp);
out1:
cred->cr_uid = t_uid;
cred->cr_groups[0] = t_gid;
p->p_ucred = cred;
crfree(tmpcred);
return (error);
}

26
sys/kern/vfs_syscalls.c
View File

@ -1593,15 +1593,25 @@ access(p, uap)
syscallarg(int) flags;
} */ *uap;
{
register struct ucred *cred = p->p_ucred;
struct ucred *cred, *tmpcred;
register struct vnode *vp;
int error, flags, t_gid, t_uid;
int error, flags;
struct nameidata nd;
t_uid = cred->cr_uid;
t_gid = cred->cr_groups[0];
cred->cr_uid = p->p_cred->p_ruid;
cred->cr_groups[0] = p->p_cred->p_rgid;
cred = p->p_ucred;
/*
* Create and modify a temporary credential instead of one that
* is potentially shared. This could also mess up socket
* buffer accounting which can run in an interrupt context.
*
* XXX - Depending on how "threads" are finally implemented, it
* may be better to explicitly pass the credential to namei()
* rather than to modify the potentially shared process structure.
*/
tmpcred = crdup(cred);
tmpcred->cr_uid = p->p_cred->p_ruid;
tmpcred->cr_groups[0] = p->p_cred->p_rgid;
p->p_ucred = tmpcred;
NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | NOOBJ, UIO_USERSPACE,
SCARG(uap, path), p);
if ((error = namei(&nd)) != 0)
@ -1623,8 +1633,8 @@ access(p, uap)
NDFREE(&nd, NDF_ONLY_PNBUF);
vput(vp);
out1:
cred->cr_uid = t_uid;
cred->cr_groups[0] = t_gid;
p->p_ucred = cred;
crfree(tmpcred);
return (error);
}