Subject: [merged] hpet-allow-user-controlled-mmap-for-user-processes.patch removed from -mm tree To: prarit@xxxxxxxxxx,clemens@xxxxxxxxxx,msw@xxxxxxxxxx,rdunlap@xxxxxxxxxxxxx,tomas.winkler@xxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Wed, 13 Nov 2013 12:39:44 -0800 The patch titled Subject: drivers/char/hpet.c: allow user controlled mmap for user processes has been removed from the -mm tree. Its filename was hpet-allow-user-controlled-mmap-for-user-processes.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Prarit Bhargava <prarit@xxxxxxxxxx> Subject: drivers/char/hpet.c: allow user controlled mmap for user processes The CONFIG_HPET_MMAP Kconfig option exposes the memory map of the HPET registers to userspace. The Kconfig help points out that in some cases this can be a security risk as some systems may erroneously configure the map such that additional data is exposed to userspace. This is a problem for distributions -- some users want the MMAP functionality but it comes with a significant security risk. In an effort to mitigate this risk, and due to the low number of users of the MMAP functionality, I've introduced a kernel parameter, hpet_mmap_enable, that is required in order to actually have the HPET MMAP exposed. Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx> Acked-by: Matt Wilson <msw@xxxxxxxxxx> Signed-off-by: Clemens Ladisch <clemens@xxxxxxxxxx> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Tomas Winkler <tomas.winkler@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/kernel-parameters.txt | 3 +++ drivers/char/Kconfig | 10 ++++++++-- drivers/char/hpet.c | 24 ++++++++++++++++++++++-- 3 files changed, 33 insertions(+), 4 deletions(-) diff -puN Documentation/kernel-parameters.txt~hpet-allow-user-controlled-mmap-for-user-processes Documentation/kernel-parameters.txt --- a/Documentation/kernel-parameters.txt~hpet-allow-user-controlled-mmap-for-user-processes +++ a/Documentation/kernel-parameters.txt @@ -1070,6 +1070,9 @@ bytes respectively. Such letter suffixes VIA, nVidia) verbose: show contents of HPET registers during setup + hpet_mmap= [X86, HPET_MMAP] Allow userspace to mmap HPET + registers. Default set by CONFIG_HPET_MMAP_DEFAULT. + hugepages= [HW,X86-32,IA-64] HugeTLB pages to allocate at boot. hugepagesz= [HW,IA-64,PPC,X86-64] The size of the HugeTLB pages. On x86-64 and powerpc, this option can be specified diff -puN drivers/char/Kconfig~hpet-allow-user-controlled-mmap-for-user-processes drivers/char/Kconfig --- a/drivers/char/Kconfig~hpet-allow-user-controlled-mmap-for-user-processes +++ a/drivers/char/Kconfig @@ -522,10 +522,16 @@ config HPET_MMAP If you say Y here, user applications will be able to mmap the HPET registers. +config HPET_MMAP_DEFAULT + bool "Enable HPET MMAP access by default" + default y + depends on HPET_MMAP + help In some hardware implementations, the page containing HPET registers may also contain other things that shouldn't be - exposed to the user. If this applies to your hardware, - say N here. + exposed to the user. This option selects the default (if + kernel parameter hpet_mmap is not set) user access to the + registers for applications that require it. config HANGCHECK_TIMER tristate "Hangcheck timer" diff -puN drivers/char/hpet.c~hpet-allow-user-controlled-mmap-for-user-processes drivers/char/hpet.c --- a/drivers/char/hpet.c~hpet-allow-user-controlled-mmap-for-user-processes +++ a/drivers/char/hpet.c @@ -367,12 +367,29 @@ static unsigned int hpet_poll(struct fil return 0; } +#ifdef CONFIG_HPET_MMAP +#ifdef CONFIG_HPET_MMAP_DEFAULT +static int hpet_mmap_enabled = 1; +#else +static int hpet_mmap_enabled = 0; +#endif + +static __init int hpet_mmap_enable(char *str) +{ + get_option(&str, &hpet_mmap_enabled); + pr_info("HPET mmap %s\n", hpet_mmap_enabled ? "enabled" : "disabled"); + return 1; +} +__setup("hpet_mmap", hpet_mmap_enable); + static int hpet_mmap(struct file *file, struct vm_area_struct *vma) { -#ifdef CONFIG_HPET_MMAP struct hpet_dev *devp; unsigned long addr; + if (!hpet_mmap_enabled) + return -EACCES; + devp = file->private_data; addr = devp->hd_hpets->hp_hpet_phys; @@ -381,10 +398,13 @@ static int hpet_mmap(struct file *file, vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); return vm_iomap_memory(vma, addr, PAGE_SIZE); +} #else +static int hpet_mmap(struct file *file, struct vm_area_struct *vma) +{ return -ENOSYS; -#endif } +#endif static int hpet_fasync(int fd, struct file *file, int on) { _ Patches currently in -mm which might be from prarit@xxxxxxxxxx are origin.patch linux-next.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html