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Message-Id: <201106171043.57138.ptesarik@suse.cz> Date: Fri, 17 Jun 2011 10:43:56 +0200 From: Petr Tesarik <ptesarik@...e.cz> To: Andrew Morton <akpm@...ux-foundation.org>, linux-kernel@...r.kernel.org Subject: [PATCH 01/10] Return EOF on out-of-bounds read from /dev/mem The off parameter (type loff_t) may specify an offset that cannot be represented by a long. Currently, /dev/mem wraps around, which may to cause applications to read/write incorrect regions of memory by accident. Follow the usual file semantics here and return 0 when reading or -EFBIG when writing beyond the accessible range. Signed-off-by: Petr Tesarik <ptesarik@...e.cz> --- drivers/char/mem.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-) diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 8fc04b4..f5cbd4e 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -97,6 +97,9 @@ static ssize_t read_mem(struct file *file, char __user *buf, ssize_t read, sz; char *ptr; + if (p != *ppos) + return 0; + if (!valid_phys_addr_range(p, count)) return -EFAULT; read = 0; @@ -155,6 +158,9 @@ static ssize_t write_mem(struct file *file, const char __user *buf, unsigned long copied; void *ptr; + if (p != *ppos) + return -EFBIG; + if (!valid_phys_addr_range(p, count)) return -EFAULT; -- 1.7.3.4 -- 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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