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Message-ID: <lsq.1444349548.941692189@decadent.org.uk> Date: Fri, 09 Oct 2015 01:12:28 +0100 From: Ben Hutchings <ben@...adent.org.uk> To: linux-kernel@...r.kernel.org, stable@...r.kernel.org CC: akpm@...ux-foundation.org, "NeilBrown" <neilb@...e.com>, "Benjamin Randazzo" <benjamin@...dazzo.fr> Subject: [PATCH 3.2 089/107] md: use kzalloc() when bitmap is disabled 3.2.72-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Benjamin Randazzo <benjamin@...dazzo.fr> commit b6878d9e03043695dbf3fa1caa6dfc09db225b16 upstream. In drivers/md/md.c get_bitmap_file() uses kmalloc() for creating a mdu_bitmap_file_t called "file". 5769 file = kmalloc(sizeof(*file), GFP_NOIO); 5770 if (!file) 5771 return -ENOMEM; This structure is copied to user space at the end of the function. 5786 if (err == 0 && 5787 copy_to_user(arg, file, sizeof(*file))) 5788 err = -EFAULT But if bitmap is disabled only the first byte of "file" is initialized with zero, so it's possible to read some bytes (up to 4095) of kernel space memory from user space. This is an information leak. 5775 /* bitmap disabled, zero the first byte and copy out */ 5776 if (!mddev->bitmap_info.file) 5777 file->pathname[0] = '\0'; Signed-off-by: Benjamin Randazzo <benjamin@...dazzo.fr> Signed-off-by: NeilBrown <neilb@...e.com> [bwh: Backported to 3.2: patch both possible allocation calls] Signed-off-by: Ben Hutchings <ben@...adent.org.uk> --- --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -5384,9 +5384,9 @@ static int get_bitmap_file(struct mddev int err = -ENOMEM; if (md_allow_write(mddev)) - file = kmalloc(sizeof(*file), GFP_NOIO); + file = kzalloc(sizeof(*file), GFP_NOIO); else - file = kmalloc(sizeof(*file), GFP_KERNEL); + file = kzalloc(sizeof(*file), GFP_KERNEL); if (!file) goto out; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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