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charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Fri, Nov 15, 2024 at 10:49:44AM -0800, Andrei Vagin wrote: > On Thu, Nov 14, 2024 at 12:59 AM Dan Carpenter wrote: > > > > The "arg->vec_len" variable is a u64 that comes from the user at the > > start of the function. The "arg->vec_len * sizeof(struct page_region))" > > multiplication can lead to integer wrapping. Use size_mul() to avoid > > that. > > > > Also the size_add/mul() functions work on unsigned long so for 32bit > > systems we need to ensure that "arg->vec_len" fits in an unsigned long. > > > > Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs") > > Cc: stable@vger.kernel.org > > Signed-off-by: Dan Carpenter > > Acked-by: Andrei Vagin > > > --- > > fs/proc/task_mmu.c | 4 +++- > > 1 file changed, 3 insertions(+), 1 deletion(-) > > > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > > index f57ea9b308bb..38a5a3e9cba2 100644 > > --- a/fs/proc/task_mmu.c > > +++ b/fs/proc/task_mmu.c > > @@ -2665,8 +2665,10 @@ static int pagemap_scan_get_args(struct pm_scan_arg *arg, > > return -EFAULT; > > if (!arg->vec && arg->vec_len) > > return -EINVAL; > > + if (UINT_MAX == SIZE_MAX && arg->vec_len > SIZE_MAX) > > nit: arg->vec_len > SIZE_MAX / sizeof(struct page_region) I don't like open coding integer overflow checks now that we have size_add(). Historically, we've done a poor job writing them correctly. Probably the right thing is to add the > SIZE_MAX check to size_add/mul(). #define size_add(a, b) ({ \ typeof(a) __a = (a); \ typeof(b) __b = (b); \ unsigned long __res; \ if (__a >= SIZE_MAX || __b >= SIZE_MAX) \ __res = ULONG_MAX; \ else \ __res = __size_add(__a, __b); \ __res; \ }) But I think you'd trigger compiler warnings if a or b were a u32 so probably we'd need to use a _Generic() or something. regards, dan carpenter