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Groups > linux.kernel > #1641013
| From | Al Viro <viro@ZenIV.linux.org.uk> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [git pull] uaccess-related bits of vfs.git |
| Date | 2017-05-13 23:30 +0200 |
| Message-ID | <tGMLT-Kt-1@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <tGIRY-6C1-17@gated-at.bofh.it> <tGJEl-7aE-3@gated-at.bofh.it> <tGKAq-7Ln-7@gated-at.bofh.it> <tGLZw-cm-3@gated-at.bofh.it> <tGMiR-jQ-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Sat, May 13, 2017 at 01:52:29PM -0700, Linus Torvalds wrote:
> I wouldn't change the existing "memdup_user()" interface itself, but
> if there really are users that can validly pass in a maxbyte value,
> why not add a new helper:
>
> void *memdup_user_limit(userptr, nmember, nsize, maxsize);
>
> and then have
>
> #define memdup_user(ptr,size) memdup_user_limit(ptr, size, 1, -1)
>
> or something. I definitely see a couple of memdup_user() people who do
> that "num*size" multiplication by hand, and it's very easy to get
> wrong and have an overflow.
>
> And for a kvmalloc/kvfree() interface, you *definitely* want that
> maxsize thing, since it absolutely needs an upper limit.
*nod*
Speaking of insanities around open-coded memdup_user()... Enjoy:
ias_opt = kmalloc(sizeof(struct irda_ias_set), GFP_ATOMIC);
if (ias_opt == NULL) {
err = -ENOMEM;
goto out;
}
/* Copy query to the driver. */
if (copy_from_user(ias_opt, optval, optlen)) {
Can't have it block, sir, has to be GFP_ATOMIC... Whaddya mean, "what
if copy_from_user() blocks?" As far as I can see, that came in circa
2.4.6, when local sturct irda_ias_set got switched to dynamic allocation...
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Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 03:10 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 09:00 +0200
Re: [git pull] uaccess-related bits of vfs.git Adam Borowski <kilobyte@angband.pl> - 2017-05-13 14:10 +0200
Re: [git pull] uaccess-related bits of vfs.git Brian Gerst <brgerst@gmail.com> - 2017-05-13 15:50 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 18:50 +0200
Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 18:20 +0200
Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 18:20 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 19:10 +0200
Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 19:20 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 20:10 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 20:30 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 21:20 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 21:40 +0200
Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 21:10 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 21:20 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 22:00 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 22:10 +0200
Re: [git pull] uaccess-related bits of vfs.git Geert Uytterhoeven <geert@linux-m68k.org> - 2017-05-13 22:40 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 22:50 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 22:40 +0200
Re: [git pull] uaccess-related bits of vfs.git Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-13 23:00 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 23:30 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-13 19:20 +0200
Re: [git pull] uaccess-related bits of vfs.git Ingo Molnar <mingo@kernel.org> - 2017-05-14 20:20 +0200
Re: [git pull] uaccess-related bits of vfs.git Al Viro <viro@ZenIV.linux.org.uk> - 2017-05-14 21:00 +0200
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