| Message ID | 20150122045956.1347.11508.stgit@localhost (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 15/01/21, Paul Moore wrote: > In preparation for expanded use in the kernel, make getname_kernel() > more useful by allowing it to handle any legal filename length. > > Thanks to Guenter Roeck for his suggestion to substitute memcpy() for > strlcpy(). > > CC: linux@roeck-us.net > CC: viro@zeniv.linux.org.uk > CC: linux-fsdevel@vger.kernel.org > Signed-off-by: Paul Moore <pmoore@redhat.com> Noted memcpy() difference (I assume to avoid races). Reviewed-by: Richard Guy Briggs <rgb@redhat.com> > --- > fs/namei.c | 34 ++++++++++++++++++++-------------- > 1 file changed, 20 insertions(+), 14 deletions(-) > > diff --git a/fs/namei.c b/fs/namei.c > index 9eb787e..63eaaf6 100644 > --- a/fs/namei.c > +++ b/fs/namei.c > @@ -211,32 +211,38 @@ getname(const char __user * filename) > return getname_flags(filename, 0, NULL); > } > > -/* > - * The "getname_kernel()" interface doesn't do pathnames longer > - * than EMBEDDED_NAME_MAX. Deal with it - you're a kernel user. > - */ > struct filename * > getname_kernel(const char * filename) > { > struct filename *result; > - char *kname; > - int len; > - > - len = strlen(filename); > - if (len >= EMBEDDED_NAME_MAX) > - return ERR_PTR(-ENAMETOOLONG); > + int len = strlen(filename) + 1; > > result = __getname(); > if (unlikely(!result)) > return ERR_PTR(-ENOMEM); > > - kname = (char *)result + sizeof(*result); > - result->name = kname; > + if (len <= EMBEDDED_NAME_MAX) { > + result->name = (char *)(result) + sizeof(*result); > + result->separate = false; > + } else if (len <= PATH_MAX) { > + struct filename *tmp; > + > + tmp = kmalloc(sizeof(*tmp), GFP_KERNEL); > + if (unlikely(!tmp)) { > + __putname(result); > + return ERR_PTR(-ENOMEM); > + } > + tmp->name = (char *)result; > + tmp->separate = true; > + result = tmp; > + } else { > + __putname(result); > + return ERR_PTR(-ENAMETOOLONG); > + } > + memcpy((char *)result->name, filename, len); > result->uptr = NULL; > result->aname = NULL; > - result->separate = false; > > - strlcpy(kname, filename, EMBEDDED_NAME_MAX); > return result; > } > > - RGB -- Richard Guy Briggs <rbriggs@redhat.com> Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat Remote, Ottawa, Canada Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 01/22/2015 07:53 AM, Richard Guy Briggs wrote: > On 15/01/21, Paul Moore wrote: >> In preparation for expanded use in the kernel, make getname_kernel() >> more useful by allowing it to handle any legal filename length. >> >> Thanks to Guenter Roeck for his suggestion to substitute memcpy() for >> strlcpy(). >> >> CC: linux@roeck-us.net >> CC: viro@zeniv.linux.org.uk >> CC: linux-fsdevel@vger.kernel.org >> Signed-off-by: Paul Moore <pmoore@redhat.com> > > Noted memcpy() difference (I assume to avoid races). > It is more efficient to use memcpy if the string length is known. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/namei.c b/fs/namei.c index 9eb787e..63eaaf6 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -211,32 +211,38 @@ getname(const char __user * filename) return getname_flags(filename, 0, NULL); } -/* - * The "getname_kernel()" interface doesn't do pathnames longer - * than EMBEDDED_NAME_MAX. Deal with it - you're a kernel user. - */ struct filename * getname_kernel(const char * filename) { struct filename *result; - char *kname; - int len; - - len = strlen(filename); - if (len >= EMBEDDED_NAME_MAX) - return ERR_PTR(-ENAMETOOLONG); + int len = strlen(filename) + 1; result = __getname(); if (unlikely(!result)) return ERR_PTR(-ENOMEM); - kname = (char *)result + sizeof(*result); - result->name = kname; + if (len <= EMBEDDED_NAME_MAX) { + result->name = (char *)(result) + sizeof(*result); + result->separate = false; + } else if (len <= PATH_MAX) { + struct filename *tmp; + + tmp = kmalloc(sizeof(*tmp), GFP_KERNEL); + if (unlikely(!tmp)) { + __putname(result); + return ERR_PTR(-ENOMEM); + } + tmp->name = (char *)result; + tmp->separate = true; + result = tmp; + } else { + __putname(result); + return ERR_PTR(-ENAMETOOLONG); + } + memcpy((char *)result->name, filename, len); result->uptr = NULL; result->aname = NULL; - result->separate = false; - strlcpy(kname, filename, EMBEDDED_NAME_MAX); return result; }
In preparation for expanded use in the kernel, make getname_kernel() more useful by allowing it to handle any legal filename length. Thanks to Guenter Roeck for his suggestion to substitute memcpy() for strlcpy(). CC: linux@roeck-us.net CC: viro@zeniv.linux.org.uk CC: linux-fsdevel@vger.kernel.org Signed-off-by: Paul Moore <pmoore@redhat.com> --- fs/namei.c | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html