* [PATCH 0/2] USB: EHCI: Add register array bounds to HCS ports @ 2021-08-18 4:30 Kees Cook 2021-08-18 4:30 ` [PATCH 1/2] " Kees Cook 2021-08-18 4:30 ` [PATCH 2/2] USB: EHCI: Add alias for Broadcom INSNREG Kees Cook 0 siblings, 2 replies; 9+ messages in thread From: Kees Cook @ 2021-08-18 4:30 UTC (permalink / raw) To: Greg Kroah-Hartman Cc: Kees Cook, Al Cooper, Alan Stern, Arnd Bergmann, Florian Fainelli, Andy Shevchenko, linux-kernel, linux-usb, bcm-kernel-feedback-list, linux-hardening Hi, This is cleaning up some of the remaining things to be able to apply -Warray-bounds and -Wzero-length-bounds globally. Only after doing my own version of the port_status patch did I find Arnd's earlier patches, including for the weird Broadcom stuff[1]. Anyway, here's what I got. :) No binary differences. -Kees [1] https://lore.kernel.org/lkml/20200527134320.869042-1-arnd@arndb.de/#t Kees Cook (2): USB: EHCI: Add register array bounds to HCS ports USB: EHCI: Add alias for Broadcom INSNREG drivers/usb/host/ehci-brcm.c | 11 +++++------ include/linux/usb/ehci_def.h | 38 ++++++++++++++++++++++++------------ 2 files changed, 31 insertions(+), 18 deletions(-) -- 2.30.2 ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 1/2] USB: EHCI: Add register array bounds to HCS ports 2021-08-18 4:30 [PATCH 0/2] USB: EHCI: Add register array bounds to HCS ports Kees Cook @ 2021-08-18 4:30 ` Kees Cook 2021-08-18 9:48 ` Andy Shevchenko 2021-08-18 14:44 ` Alan Stern 2021-08-18 4:30 ` [PATCH 2/2] USB: EHCI: Add alias for Broadcom INSNREG Kees Cook 1 sibling, 2 replies; 9+ messages in thread From: Kees Cook @ 2021-08-18 4:30 UTC (permalink / raw) To: Greg Kroah-Hartman Cc: Kees Cook, Arnd Bergmann, Al Cooper, Alan Stern, linux-usb, Florian Fainelli, Andy Shevchenko, linux-kernel, bcm-kernel-feedback-list, linux-hardening The original EHCI register struct used a trailing 0-element array for addressing the N_PORTS-many available registers. However, after commit a46af4ebf9ff ("USB: EHCI: define extension registers like normal ones") the 0-element array started to overlap the USBMODE extension register. To avoid future compile-time warnings about accessing indexes within a 0-element array, rearrange the struct to actually describe the expected layout (max 15 registers) with a union. All offsets remain the same, and bounds checking becomes possible on accesses to port_status and hostpc. There are no binary differences, and struct offsets continue to match. "pahole --hex -C ehci_regs" before: struct ehci_regs { u32 command; /* 0 0x4 */ u32 status; /* 0x4 0x4 */ u32 intr_enable; /* 0x8 0x4 */ u32 frame_index; /* 0xc 0x4 */ u32 segment; /* 0x10 0x4 */ u32 frame_list; /* 0x14 0x4 */ u32 async_next; /* 0x18 0x4 */ u32 reserved1[2]; /* 0x1c 0x8 */ u32 txfill_tuning; /* 0x24 0x4 */ u32 reserved2[6]; /* 0x28 0x18 */ /* --- cacheline 1 boundary (64 bytes) --- */ u32 configured_flag; /* 0x40 0x4 */ u32 port_status[0]; /* 0x44 0 */ u32 reserved3[9]; /* 0x44 0x24 */ u32 usbmode; /* 0x68 0x4 */ u32 reserved4[6]; /* 0x6c 0x18 */ /* --- cacheline 2 boundary (128 bytes) was 4 bytes ago --- */ u32 hostpc[0]; /* 0x84 0 */ u32 reserved5[17]; /* 0x84 0x44 */ /* --- cacheline 3 boundary (192 bytes) was 8 bytes ago --- */ u32 usbmode_ex; /* 0xc8 0x4 */ /* size: 204, cachelines: 4, members: 18 */ /* last cacheline: 12 bytes */ }; after: struct ehci_regs { u32 command; /* 0 0x4 */ u32 status; /* 0x4 0x4 */ u32 intr_enable; /* 0x8 0x4 */ u32 frame_index; /* 0xc 0x4 */ u32 segment; /* 0x10 0x4 */ u32 frame_list; /* 0x14 0x4 */ u32 async_next; /* 0x18 0x4 */ u32 reserved1[2]; /* 0x1c 0x8 */ u32 txfill_tuning; /* 0x24 0x4 */ u32 reserved2[6]; /* 0x28 0x18 */ /* --- cacheline 1 boundary (64 bytes) --- */ u32 configured_flag; /* 0x40 0x4 */ union { u32 port_status[15]; /* 0x44 0x3c */ struct { u32 reserved3[9]; /* 0x44 0x24 */ u32 usbmode; /* 0x68 0x4 */ }; /* 0x44 0x28 */ }; /* 0x44 0x3c */ /* --- cacheline 2 boundary (128 bytes) --- */ u32 reserved4; /* 0x80 0x4 */ u32 hostpc[15]; /* 0x84 0x3c */ /* --- cacheline 3 boundary (192 bytes) --- */ u32 reserved5[2]; /* 0xc0 0x8 */ u32 usbmode_ex; /* 0xc8 0x4 */ /* size: 204, cachelines: 4, members: 16 */ /* last cacheline: 12 bytes */ }; With this fixed, adding -Wzero-length-bounds to the build no longer produces several warnings like this: In file included from drivers/usb/host/ehci-hcd.c:306: drivers/usb/host/ehci-hub.c: In function 'ehci_port_handed_over': drivers/usb/host/ehci-hub.c:1194:8: warning: array subscript '<unknown>' is outside the bounds of an interior zero-length array 'u32[0]' {aka 'unsigned int[]'} [-Wzero-length-bounds] 1194 | reg = &ehci->regs->port_status[portnum - 1]; | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from drivers/usb/host/ehci.h:274, from drivers/usb/host/ehci-hcd.c:97: ./include/linux/usb/ehci_def.h:130:7: note: while referencing 'port_status' 130 | u32 port_status[0]; /* up to N_PORTS */ | ^~~~~~~~~~~ Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Al Cooper <alcooperx@gmail.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: linux-usb@vger.kernel.org Fixes: a46af4ebf9ff ("USB: EHCI: define extension registers like normal ones") Signed-off-by: Kees Cook <keescook@chromium.org> --- include/linux/usb/ehci_def.h | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/include/linux/usb/ehci_def.h b/include/linux/usb/ehci_def.h index 78e006355557..5398f571113b 100644 --- a/include/linux/usb/ehci_def.h +++ b/include/linux/usb/ehci_def.h @@ -45,6 +45,7 @@ struct ehci_caps { #define HCS_PORTROUTED(p) ((p)&(1 << 7)) /* true: port routing */ #define HCS_PPC(p) ((p)&(1 << 4)) /* true: port power control */ #define HCS_N_PORTS(p) (((p)>>0)&0xf) /* bits 3:0, ports on HC */ +#define HCS_N_PORTS_MAX 0xf /* N_PORTS valid 0x1-0xF */ u32 hcc_params; /* HCCPARAMS - offset 0x8 */ /* EHCI 1.1 addendum */ @@ -126,8 +127,9 @@ struct ehci_regs { u32 configured_flag; #define FLAG_CF (1<<0) /* true: we'll support "high speed" */ - /* PORTSC: offset 0x44 */ - u32 port_status[0]; /* up to N_PORTS */ + union { + /* PORTSC: offset 0x44 */ + u32 port_status[HCS_N_PORTS_MAX]; /* EHCI 1.1 addendum */ #define PORTSC_SUSPEND_STS_ACK 0 #define PORTSC_SUSPEND_STS_NYET 1 @@ -164,28 +166,28 @@ struct ehci_regs { #define PORT_CSC (1<<1) /* connect status change */ #define PORT_CONNECT (1<<0) /* device connected */ #define PORT_RWC_BITS (PORT_CSC | PORT_PEC | PORT_OCC) - - u32 reserved3[9]; - - /* USBMODE: offset 0x68 */ - u32 usbmode; /* USB Device mode */ + struct { + u32 reserved3[9]; + /* USBMODE: offset 0x68 */ + u32 usbmode; /* USB Device mode */ + }; #define USBMODE_SDIS (1<<3) /* Stream disable */ #define USBMODE_BE (1<<2) /* BE/LE endianness select */ #define USBMODE_CM_HC (3<<0) /* host controller mode */ #define USBMODE_CM_IDLE (0<<0) /* idle state */ - - u32 reserved4[6]; + }; + u32 reserved4; /* Moorestown has some non-standard registers, partially due to the fact that * its EHCI controller has both TT and LPM support. HOSTPCx are extensions to * PORTSCx */ /* HOSTPC: offset 0x84 */ - u32 hostpc[0]; /* HOSTPC extension */ + u32 hostpc[HCS_N_PORTS_MAX]; #define HOSTPC_PHCD (1<<22) /* Phy clock disable */ #define HOSTPC_PSPD (3<<25) /* Port speed detection */ - u32 reserved5[17]; + u32 reserved5[2]; /* USBMODE_EX: offset 0xc8 */ u32 usbmode_ex; /* USB Device mode extension */ -- 2.30.2 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] USB: EHCI: Add register array bounds to HCS ports 2021-08-18 4:30 ` [PATCH 1/2] " Kees Cook @ 2021-08-18 9:48 ` Andy Shevchenko 2021-08-18 15:02 ` Alan Stern 2021-08-18 14:44 ` Alan Stern 1 sibling, 1 reply; 9+ messages in thread From: Andy Shevchenko @ 2021-08-18 9:48 UTC (permalink / raw) To: Kees Cook Cc: Greg Kroah-Hartman, Arnd Bergmann, Al Cooper, Alan Stern, linux-usb, Florian Fainelli, linux-kernel, bcm-kernel-feedback-list, linux-hardening On Wed, Aug 18, 2021 at 7:30 AM Kees Cook <keescook@chromium.org> wrote: > > The original EHCI register struct used a trailing 0-element array for > addressing the N_PORTS-many available registers. However, after > commit a46af4ebf9ff ("USB: EHCI: define extension registers like normal ones") > the 0-element array started to overlap the USBMODE extension register. > > To avoid future compile-time warnings about accessing indexes within a > 0-element array, rearrange the struct to actually describe the expected > layout (max 15 registers) with a union. All offsets remain the same, and > bounds checking becomes possible on accesses to port_status and hostpc. ... > /* HOSTPC: offset 0x84 */ > - u32 hostpc[0]; /* HOSTPC extension */ > + u32 hostpc[HCS_N_PORTS_MAX]; > #define HOSTPC_PHCD (1<<22) /* Phy clock disable */ > #define HOSTPC_PSPD (3<<25) /* Port speed detection */ > > - u32 reserved5[17]; > + u32 reserved5[2]; Shouldn't it be rather [17 - PORT_MAX]? for accuracy? Or also a union approach? -- With Best Regards, Andy Shevchenko ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] USB: EHCI: Add register array bounds to HCS ports 2021-08-18 9:48 ` Andy Shevchenko @ 2021-08-18 15:02 ` Alan Stern 0 siblings, 0 replies; 9+ messages in thread From: Alan Stern @ 2021-08-18 15:02 UTC (permalink / raw) To: Andy Shevchenko Cc: Kees Cook, Greg Kroah-Hartman, Arnd Bergmann, Al Cooper, linux-usb, Florian Fainelli, linux-kernel, bcm-kernel-feedback-list, linux-hardening On Wed, Aug 18, 2021 at 12:48:17PM +0300, Andy Shevchenko wrote: > On Wed, Aug 18, 2021 at 7:30 AM Kees Cook <keescook@chromium.org> wrote: > > > > The original EHCI register struct used a trailing 0-element array for > > addressing the N_PORTS-many available registers. However, after > > commit a46af4ebf9ff ("USB: EHCI: define extension registers like normal ones") > > the 0-element array started to overlap the USBMODE extension register. > > > > To avoid future compile-time warnings about accessing indexes within a > > 0-element array, rearrange the struct to actually describe the expected > > layout (max 15 registers) with a union. All offsets remain the same, and > > bounds checking becomes possible on accesses to port_status and hostpc. > > ... > > > /* HOSTPC: offset 0x84 */ > > - u32 hostpc[0]; /* HOSTPC extension */ > > + u32 hostpc[HCS_N_PORTS_MAX]; > > #define HOSTPC_PHCD (1<<22) /* Phy clock disable */ > > #define HOSTPC_PSPD (3<<25) /* Port speed detection */ > > > > - u32 reserved5[17]; > > + u32 reserved5[2]; > > Shouldn't it be rather [17 - PORT_MAX]? for accuracy? > Or also a union approach? It's okay to use [2] here. The only purpose is to ensure that the following usbmode_ex field is allocated at offset 0xc8; there's no special intrinsic meaning to that 17 value. Alan Stern ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] USB: EHCI: Add register array bounds to HCS ports 2021-08-18 4:30 ` [PATCH 1/2] " Kees Cook 2021-08-18 9:48 ` Andy Shevchenko @ 2021-08-18 14:44 ` Alan Stern 2021-08-18 17:17 ` Kees Cook 1 sibling, 1 reply; 9+ messages in thread From: Alan Stern @ 2021-08-18 14:44 UTC (permalink / raw) To: Kees Cook Cc: Greg Kroah-Hartman, Arnd Bergmann, Al Cooper, linux-usb, Florian Fainelli, Andy Shevchenko, linux-kernel, bcm-kernel-feedback-list, linux-hardening On Tue, Aug 17, 2021 at 09:30:33PM -0700, Kees Cook wrote: > The original EHCI register struct used a trailing 0-element array for > addressing the N_PORTS-many available registers. However, after > commit a46af4ebf9ff ("USB: EHCI: define extension registers like normal ones") > the 0-element array started to overlap the USBMODE extension register. > > To avoid future compile-time warnings about accessing indexes within a > 0-element array, rearrange the struct to actually describe the expected > layout (max 15 registers) with a union. All offsets remain the same, and > bounds checking becomes possible on accesses to port_status and hostpc. > > There are no binary differences, and struct offsets continue to match. Two comments... > --- > include/linux/usb/ehci_def.h | 24 +++++++++++++----------- > 1 file changed, 13 insertions(+), 11 deletions(-) > > diff --git a/include/linux/usb/ehci_def.h b/include/linux/usb/ehci_def.h > index 78e006355557..5398f571113b 100644 > --- a/include/linux/usb/ehci_def.h > +++ b/include/linux/usb/ehci_def.h > @@ -45,6 +45,7 @@ struct ehci_caps { > #define HCS_PORTROUTED(p) ((p)&(1 << 7)) /* true: port routing */ > #define HCS_PPC(p) ((p)&(1 << 4)) /* true: port power control */ > #define HCS_N_PORTS(p) (((p)>>0)&0xf) /* bits 3:0, ports on HC */ > +#define HCS_N_PORTS_MAX 0xf /* N_PORTS valid 0x1-0xF */ I would prefer to see this value in decimal. It seems very odd to say something like "The maximum number of ports is 0xf". > > u32 hcc_params; /* HCCPARAMS - offset 0x8 */ > /* EHCI 1.1 addendum */ > @@ -126,8 +127,9 @@ struct ehci_regs { > u32 configured_flag; > #define FLAG_CF (1<<0) /* true: we'll support "high speed" */ > > - /* PORTSC: offset 0x44 */ > - u32 port_status[0]; /* up to N_PORTS */ > + union { > + /* PORTSC: offset 0x44 */ > + u32 port_status[HCS_N_PORTS_MAX]; Please don't lose the second comment. > /* EHCI 1.1 addendum */ > #define PORTSC_SUSPEND_STS_ACK 0 > #define PORTSC_SUSPEND_STS_NYET 1 > @@ -164,28 +166,28 @@ struct ehci_regs { > #define PORT_CSC (1<<1) /* connect status change */ > #define PORT_CONNECT (1<<0) /* device connected */ > #define PORT_RWC_BITS (PORT_CSC | PORT_PEC | PORT_OCC) > - > - u32 reserved3[9]; > - > - /* USBMODE: offset 0x68 */ > - u32 usbmode; /* USB Device mode */ > + struct { > + u32 reserved3[9]; > + /* USBMODE: offset 0x68 */ > + u32 usbmode; /* USB Device mode */ > + }; > #define USBMODE_SDIS (1<<3) /* Stream disable */ > #define USBMODE_BE (1<<2) /* BE/LE endianness select */ > #define USBMODE_CM_HC (3<<0) /* host controller mode */ > #define USBMODE_CM_IDLE (0<<0) /* idle state */ > - > - u32 reserved4[6]; > + }; > + u32 reserved4; > > /* Moorestown has some non-standard registers, partially due to the fact that > * its EHCI controller has both TT and LPM support. HOSTPCx are extensions to > * PORTSCx > */ > /* HOSTPC: offset 0x84 */ > - u32 hostpc[0]; /* HOSTPC extension */ > + u32 hostpc[HCS_N_PORTS_MAX]; > #define HOSTPC_PHCD (1<<22) /* Phy clock disable */ > #define HOSTPC_PSPD (3<<25) /* Port speed detection */ > > - u32 reserved5[17]; > + u32 reserved5[2]; > > /* USBMODE_EX: offset 0xc8 */ > u32 usbmode_ex; /* USB Device mode extension */ Otherwise okay. Alan Stern ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 1/2] USB: EHCI: Add register array bounds to HCS ports 2021-08-18 14:44 ` Alan Stern @ 2021-08-18 17:17 ` Kees Cook 0 siblings, 0 replies; 9+ messages in thread From: Kees Cook @ 2021-08-18 17:17 UTC (permalink / raw) To: Alan Stern Cc: Greg Kroah-Hartman, Arnd Bergmann, Al Cooper, linux-usb, Florian Fainelli, Andy Shevchenko, linux-kernel, bcm-kernel-feedback-list, linux-hardening On Wed, Aug 18, 2021 at 10:44:42AM -0400, Alan Stern wrote: > On Tue, Aug 17, 2021 at 09:30:33PM -0700, Kees Cook wrote: > > The original EHCI register struct used a trailing 0-element array for > > addressing the N_PORTS-many available registers. However, after > > commit a46af4ebf9ff ("USB: EHCI: define extension registers like normal ones") > > the 0-element array started to overlap the USBMODE extension register. > > > > To avoid future compile-time warnings about accessing indexes within a > > 0-element array, rearrange the struct to actually describe the expected > > layout (max 15 registers) with a union. All offsets remain the same, and > > bounds checking becomes possible on accesses to port_status and hostpc. > > > > There are no binary differences, and struct offsets continue to match. > > Two comments... > > > --- > > include/linux/usb/ehci_def.h | 24 +++++++++++++----------- > > 1 file changed, 13 insertions(+), 11 deletions(-) > > > > diff --git a/include/linux/usb/ehci_def.h b/include/linux/usb/ehci_def.h > > index 78e006355557..5398f571113b 100644 > > --- a/include/linux/usb/ehci_def.h > > +++ b/include/linux/usb/ehci_def.h > > @@ -45,6 +45,7 @@ struct ehci_caps { > > #define HCS_PORTROUTED(p) ((p)&(1 << 7)) /* true: port routing */ > > #define HCS_PPC(p) ((p)&(1 << 4)) /* true: port power control */ > > #define HCS_N_PORTS(p) (((p)>>0)&0xf) /* bits 3:0, ports on HC */ > > +#define HCS_N_PORTS_MAX 0xf /* N_PORTS valid 0x1-0xF */ > > I would prefer to see this value in decimal. It seems very odd to say > something like "The maximum number of ports is 0xf". Okay, done. > > > > > u32 hcc_params; /* HCCPARAMS - offset 0x8 */ > > /* EHCI 1.1 addendum */ > > @@ -126,8 +127,9 @@ struct ehci_regs { > > u32 configured_flag; > > #define FLAG_CF (1<<0) /* true: we'll support "high speed" */ > > > > - /* PORTSC: offset 0x44 */ > > - u32 port_status[0]; /* up to N_PORTS */ > > + union { > > + /* PORTSC: offset 0x44 */ > > + u32 port_status[HCS_N_PORTS_MAX]; > > Please don't lose the second comment. I've put it back. It seemed redundant in the face of HCS_N_PORTS_MAX being there now. > > > /* EHCI 1.1 addendum */ > > #define PORTSC_SUSPEND_STS_ACK 0 > > #define PORTSC_SUSPEND_STS_NYET 1 > > @@ -164,28 +166,28 @@ struct ehci_regs { > > #define PORT_CSC (1<<1) /* connect status change */ > > #define PORT_CONNECT (1<<0) /* device connected */ > > #define PORT_RWC_BITS (PORT_CSC | PORT_PEC | PORT_OCC) > > - > > - u32 reserved3[9]; > > - > > - /* USBMODE: offset 0x68 */ > > - u32 usbmode; /* USB Device mode */ > > + struct { > > + u32 reserved3[9]; > > + /* USBMODE: offset 0x68 */ > > + u32 usbmode; /* USB Device mode */ > > + }; > > #define USBMODE_SDIS (1<<3) /* Stream disable */ > > #define USBMODE_BE (1<<2) /* BE/LE endianness select */ > > #define USBMODE_CM_HC (3<<0) /* host controller mode */ > > #define USBMODE_CM_IDLE (0<<0) /* idle state */ > > - > > - u32 reserved4[6]; > > + }; > > + u32 reserved4; > > > > /* Moorestown has some non-standard registers, partially due to the fact that > > * its EHCI controller has both TT and LPM support. HOSTPCx are extensions to > > * PORTSCx > > */ > > /* HOSTPC: offset 0x84 */ > > - u32 hostpc[0]; /* HOSTPC extension */ > > + u32 hostpc[HCS_N_PORTS_MAX]; > > #define HOSTPC_PHCD (1<<22) /* Phy clock disable */ > > #define HOSTPC_PSPD (3<<25) /* Port speed detection */ > > > > - u32 reserved5[17]; > > + u32 reserved5[2]; > > > > /* USBMODE_EX: offset 0xc8 */ > > u32 usbmode_ex; /* USB Device mode extension */ > > Otherwise okay. Thanks! -- Kees Cook ^ permalink raw reply [flat|nested] 9+ messages in thread
* [PATCH 2/2] USB: EHCI: Add alias for Broadcom INSNREG 2021-08-18 4:30 [PATCH 0/2] USB: EHCI: Add register array bounds to HCS ports Kees Cook 2021-08-18 4:30 ` [PATCH 1/2] " Kees Cook @ 2021-08-18 4:30 ` Kees Cook 2021-08-18 14:57 ` Alan Stern 1 sibling, 1 reply; 9+ messages in thread From: Kees Cook @ 2021-08-18 4:30 UTC (permalink / raw) To: Greg Kroah-Hartman Cc: Kees Cook, Al Cooper, Alan Stern, linux-usb, bcm-kernel-feedback-list, Arnd Bergmann, Florian Fainelli, Andy Shevchenko, linux-kernel, linux-hardening Refactor struct ehci_regs to avoid accessing beyond the end of port_status. This change results in no difference in the resulting object code. Avoids several warnings when building with -Warray-bounds: drivers/usb/host/ehci-brcm.c: In function 'ehci_brcm_reset': drivers/usb/host/ehci-brcm.c:113:32: warning: array subscript 16 is above array bounds of 'u32[15]' {aka 'unsigned int[15]'} [-Warray-bounds] 113 | ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In file included from drivers/usb/host/ehci.h:274, from drivers/usb/host/ehci-brcm.c:15: ./include/linux/usb/ehci_def.h:132:7: note: while referencing 'port_status' 132 | u32 port_status[HCS_N_PORTS_MAX]; | ^~~~~~~~~~~ Note that the documentation around this proprietary register is confusing. If "USB_EHCI_INSNREG00" is at port_status[0x0f], its offset would be 0x80 (not 0x90). The code uses port_status[0x10], so is that not using "USB_EHCI_INSNREG00"? Perhaps port_status[0x10] is USB_EHCI_INSNREG01 and port_status[0x12] is USB_EHCI_INSNREG03? If so, the union could be adjusted to better represent the layout. Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Al Cooper <alcooperx@gmail.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: linux-usb@vger.kernel.org Cc: bcm-kernel-feedback-list@broadcom.com Suggested-by: Arnd Bergmann <arnd@arndb.de> Fixes: 9df231511bd6 ("usb: ehci: Add new EHCI driver for Broadcom STB SoC's") Signed-off-by: Kees Cook <keescook@chromium.org> --- drivers/usb/host/ehci-brcm.c | 11 +++++------ include/linux/usb/ehci_def.h | 16 ++++++++++++++-- 2 files changed, 19 insertions(+), 8 deletions(-) diff --git a/drivers/usb/host/ehci-brcm.c b/drivers/usb/host/ehci-brcm.c index 3e0ebe8cc649..5d232d3701f9 100644 --- a/drivers/usb/host/ehci-brcm.c +++ b/drivers/usb/host/ehci-brcm.c @@ -110,8 +110,8 @@ static int ehci_brcm_reset(struct usb_hcd *hcd) * bus usage * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90 */ - ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); - ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]); + ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[0]); + ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[2]); return ehci_setup(hcd); } @@ -223,11 +223,10 @@ static int __maybe_unused ehci_brcm_resume(struct device *dev) /* * SWLINUX-1705: Avoid OUT packet underflows during high memory * bus usage - * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 - * @ 0x90 + * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90 */ - ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); - ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]); + ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[0]); + ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[2]); ehci_resume(hcd, false); diff --git a/include/linux/usb/ehci_def.h b/include/linux/usb/ehci_def.h index 5398f571113b..86f0909cab99 100644 --- a/include/linux/usb/ehci_def.h +++ b/include/linux/usb/ehci_def.h @@ -182,11 +182,23 @@ struct ehci_regs { * its EHCI controller has both TT and LPM support. HOSTPCx are extensions to * PORTSCx */ - /* HOSTPC: offset 0x84 */ - u32 hostpc[HCS_N_PORTS_MAX]; + union { + /* HOSTPC: offset 0x84 */ + u32 hostpc[HCS_N_PORTS_MAX]; #define HOSTPC_PHCD (1<<22) /* Phy clock disable */ #define HOSTPC_PSPD (3<<25) /* Port speed detection */ + /* + * This was originally documented as: + * "port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90" + * but this doesn't make sense: the code was using + * port_status[0x10]. port_status[0x0f] would be reserved4. + * Also, none of these are near 0x90. port_status[0x10] is + * offset 0x84, and port_status[0x0f] would be 0x80. + */ + u32 brcm_insnreg[3]; + }; + u32 reserved5[2]; /* USBMODE_EX: offset 0xc8 */ -- 2.30.2 ^ permalink raw reply related [flat|nested] 9+ messages in thread
* Re: [PATCH 2/2] USB: EHCI: Add alias for Broadcom INSNREG 2021-08-18 4:30 ` [PATCH 2/2] USB: EHCI: Add alias for Broadcom INSNREG Kees Cook @ 2021-08-18 14:57 ` Alan Stern 2021-08-18 17:15 ` Kees Cook 0 siblings, 1 reply; 9+ messages in thread From: Alan Stern @ 2021-08-18 14:57 UTC (permalink / raw) To: Kees Cook Cc: Greg Kroah-Hartman, Al Cooper, linux-usb, bcm-kernel-feedback-list, Arnd Bergmann, Florian Fainelli, Andy Shevchenko, linux-kernel, linux-hardening On Tue, Aug 17, 2021 at 09:30:34PM -0700, Kees Cook wrote: > Refactor struct ehci_regs to avoid accessing beyond the end of > port_status. This change results in no difference in the resulting > object code. > > Avoids several warnings when building with -Warray-bounds: > > drivers/usb/host/ehci-brcm.c: In function 'ehci_brcm_reset': > drivers/usb/host/ehci-brcm.c:113:32: warning: array subscript 16 is above array bounds of 'u32[15]' {aka 'unsigned int[15]'} [-Warray-bounds] > 113 | ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > In file included from drivers/usb/host/ehci.h:274, > from drivers/usb/host/ehci-brcm.c:15: > ./include/linux/usb/ehci_def.h:132:7: note: while referencing 'port_status' > 132 | u32 port_status[HCS_N_PORTS_MAX]; > | ^~~~~~~~~~~ > > Note that the documentation around this proprietary register is > confusing. If "USB_EHCI_INSNREG00" is at port_status[0x0f], its offset > would be 0x80 (not 0x90). The code uses port_status[0x10], so is that > not using "USB_EHCI_INSNREG00"? I suspect the 0x90 value in the comment is a typo for 0x80. > Perhaps port_status[0x10] is USB_EHCI_INSNREG01 and port_status[0x12] > is USB_EHCI_INSNREG03? If so, the union could be adjusted to better > represent the layout. > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: Al Cooper <alcooperx@gmail.com> > Cc: Alan Stern <stern@rowland.harvard.edu> > Cc: linux-usb@vger.kernel.org > Cc: bcm-kernel-feedback-list@broadcom.com > Suggested-by: Arnd Bergmann <arnd@arndb.de> > Fixes: 9df231511bd6 ("usb: ehci: Add new EHCI driver for Broadcom STB SoC's") > Signed-off-by: Kees Cook <keescook@chromium.org> > --- > drivers/usb/host/ehci-brcm.c | 11 +++++------ > include/linux/usb/ehci_def.h | 16 ++++++++++++++-- > 2 files changed, 19 insertions(+), 8 deletions(-) > > diff --git a/drivers/usb/host/ehci-brcm.c b/drivers/usb/host/ehci-brcm.c > index 3e0ebe8cc649..5d232d3701f9 100644 > --- a/drivers/usb/host/ehci-brcm.c > +++ b/drivers/usb/host/ehci-brcm.c > @@ -110,8 +110,8 @@ static int ehci_brcm_reset(struct usb_hcd *hcd) > * bus usage > * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90 This last comment line is no longer necessary, thanks to the revised port definitions. And since it is actively misleading, with the 0x90 instead of 0x80, I think it should be removed entirely. > */ > - ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); > - ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]); > + ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[0]); > + ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[2]); > > return ehci_setup(hcd); > } > @@ -223,11 +223,10 @@ static int __maybe_unused ehci_brcm_resume(struct device *dev) > /* > * SWLINUX-1705: Avoid OUT packet underflows during high memory > * bus usage > - * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 > - * @ 0x90 > + * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90 Same here. > */ > - ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); > - ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]); > + ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[0]); > + ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[2]); > > ehci_resume(hcd, false); > > diff --git a/include/linux/usb/ehci_def.h b/include/linux/usb/ehci_def.h > index 5398f571113b..86f0909cab99 100644 > --- a/include/linux/usb/ehci_def.h > +++ b/include/linux/usb/ehci_def.h > @@ -182,11 +182,23 @@ struct ehci_regs { > * its EHCI controller has both TT and LPM support. HOSTPCx are extensions to > * PORTSCx > */ > - /* HOSTPC: offset 0x84 */ > - u32 hostpc[HCS_N_PORTS_MAX]; > + union { > + /* HOSTPC: offset 0x84 */ > + u32 hostpc[HCS_N_PORTS_MAX]; > #define HOSTPC_PHCD (1<<22) /* Phy clock disable */ > #define HOSTPC_PSPD (3<<25) /* Port speed detection */ > > + /* > + * This was originally documented as: > + * "port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90" > + * but this doesn't make sense: the code was using > + * port_status[0x10]. port_status[0x0f] would be reserved4. > + * Also, none of these are near 0x90. port_status[0x10] is > + * offset 0x84, and port_status[0x0f] would be 0x80. > + */ This comment is entirely inappropriate. It's the sort of thing that belongs in the git history, not in the code. > + u32 brcm_insnreg[3]; Given the notation in the original comments, perhaps it would be better to define this as: struct { /* Broadcom proprietary registers */ u32 brcm_insnreg01; /* offset 0x84 */ u32 brcm_insnreg02; u32 brcm_insnreg03; }; I don't know. It would be nice to hear from somebody at Broadcom. Alan Stern > + }; > + > u32 reserved5[2]; > > /* USBMODE_EX: offset 0xc8 */ > -- > 2.30.2 > ^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH 2/2] USB: EHCI: Add alias for Broadcom INSNREG 2021-08-18 14:57 ` Alan Stern @ 2021-08-18 17:15 ` Kees Cook 0 siblings, 0 replies; 9+ messages in thread From: Kees Cook @ 2021-08-18 17:15 UTC (permalink / raw) To: Alan Stern Cc: Greg Kroah-Hartman, Al Cooper, linux-usb, bcm-kernel-feedback-list, Arnd Bergmann, Florian Fainelli, Andy Shevchenko, linux-kernel, linux-hardening On Wed, Aug 18, 2021 at 10:57:36AM -0400, Alan Stern wrote: > On Tue, Aug 17, 2021 at 09:30:34PM -0700, Kees Cook wrote: > > Refactor struct ehci_regs to avoid accessing beyond the end of > > port_status. This change results in no difference in the resulting > > object code. > > > > Avoids several warnings when building with -Warray-bounds: > > > > drivers/usb/host/ehci-brcm.c: In function 'ehci_brcm_reset': > > drivers/usb/host/ehci-brcm.c:113:32: warning: array subscript 16 is above array bounds of 'u32[15]' {aka 'unsigned int[15]'} [-Warray-bounds] > > 113 | ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > In file included from drivers/usb/host/ehci.h:274, > > from drivers/usb/host/ehci-brcm.c:15: > > ./include/linux/usb/ehci_def.h:132:7: note: while referencing 'port_status' > > 132 | u32 port_status[HCS_N_PORTS_MAX]; > > | ^~~~~~~~~~~ > > > > Note that the documentation around this proprietary register is > > confusing. If "USB_EHCI_INSNREG00" is at port_status[0x0f], its offset > > would be 0x80 (not 0x90). The code uses port_status[0x10], so is that > > not using "USB_EHCI_INSNREG00"? > > I suspect the 0x90 value in the comment is a typo for 0x80. That'd be my conclusion too. I've updated this for v2. > > > Perhaps port_status[0x10] is USB_EHCI_INSNREG01 and port_status[0x12] > > is USB_EHCI_INSNREG03? If so, the union could be adjusted to better > > represent the layout. > > > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Cc: Al Cooper <alcooperx@gmail.com> > > Cc: Alan Stern <stern@rowland.harvard.edu> > > Cc: linux-usb@vger.kernel.org > > Cc: bcm-kernel-feedback-list@broadcom.com > > Suggested-by: Arnd Bergmann <arnd@arndb.de> > > Fixes: 9df231511bd6 ("usb: ehci: Add new EHCI driver for Broadcom STB SoC's") > > Signed-off-by: Kees Cook <keescook@chromium.org> > > --- > > drivers/usb/host/ehci-brcm.c | 11 +++++------ > > include/linux/usb/ehci_def.h | 16 ++++++++++++++-- > > 2 files changed, 19 insertions(+), 8 deletions(-) > > > > diff --git a/drivers/usb/host/ehci-brcm.c b/drivers/usb/host/ehci-brcm.c > > index 3e0ebe8cc649..5d232d3701f9 100644 > > --- a/drivers/usb/host/ehci-brcm.c > > +++ b/drivers/usb/host/ehci-brcm.c > > @@ -110,8 +110,8 @@ static int ehci_brcm_reset(struct usb_hcd *hcd) > > * bus usage > > * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90 > > This last comment line is no longer necessary, thanks to the revised > port definitions. And since it is actively misleading, with the 0x90 > instead of 0x80, I think it should be removed entirely. Done. > > > */ > > - ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); > > - ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]); > > + ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[0]); > > + ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[2]); > > > > return ehci_setup(hcd); > > } > > @@ -223,11 +223,10 @@ static int __maybe_unused ehci_brcm_resume(struct device *dev) > > /* > > * SWLINUX-1705: Avoid OUT packet underflows during high memory > > * bus usage > > - * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 > > - * @ 0x90 > > + * port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90 > > Same here. > > > */ > > - ehci_writel(ehci, 0x00800040, &ehci->regs->port_status[0x10]); > > - ehci_writel(ehci, 0x00000001, &ehci->regs->port_status[0x12]); > > + ehci_writel(ehci, 0x00800040, &ehci->regs->brcm_insnreg[0]); > > + ehci_writel(ehci, 0x00000001, &ehci->regs->brcm_insnreg[2]); > > > > ehci_resume(hcd, false); > > > > diff --git a/include/linux/usb/ehci_def.h b/include/linux/usb/ehci_def.h > > index 5398f571113b..86f0909cab99 100644 > > --- a/include/linux/usb/ehci_def.h > > +++ b/include/linux/usb/ehci_def.h > > @@ -182,11 +182,23 @@ struct ehci_regs { > > * its EHCI controller has both TT and LPM support. HOSTPCx are extensions to > > * PORTSCx > > */ > > - /* HOSTPC: offset 0x84 */ > > - u32 hostpc[HCS_N_PORTS_MAX]; > > + union { > > + /* HOSTPC: offset 0x84 */ > > + u32 hostpc[HCS_N_PORTS_MAX]; > > #define HOSTPC_PHCD (1<<22) /* Phy clock disable */ > > #define HOSTPC_PSPD (3<<25) /* Port speed detection */ > > > > + /* > > + * This was originally documented as: > > + * "port_status[0x0f] = Broadcom-proprietary USB_EHCI_INSNREG00 @ 0x90" > > + * but this doesn't make sense: the code was using > > + * port_status[0x10]. port_status[0x0f] would be reserved4. > > + * Also, none of these are near 0x90. port_status[0x10] is > > + * offset 0x84, and port_status[0x0f] would be 0x80. > > + */ > > This comment is entirely inappropriate. It's the sort of thing that > belongs in the git history, not in the code. I wanted it to be easily discoverable, but since we've got a preferred result now, I'm dropping this and orienting against 0x80. > > > + u32 brcm_insnreg[3]; > > Given the notation in the original comments, perhaps it would be better > to define this as: > > struct { /* Broadcom proprietary registers */ > u32 brcm_insnreg01; /* offset 0x84 */ > u32 brcm_insnreg02; > u32 brcm_insnreg03; > }; Following the other register arrays, I'm going to keep an array for this, but adjust the numbering to start at 0 @ 0x80 so the code will poke offset 1 and 3. > I don't know. It would be nice to hear from somebody at Broadcom. Agreed. :) Thanks for the review! -- Kees Cook ^ permalink raw reply [flat|nested] 9+ messages in thread
end of thread, other threads:[~2021-08-18 17:17 UTC | newest] Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-08-18 4:30 [PATCH 0/2] USB: EHCI: Add register array bounds to HCS ports Kees Cook 2021-08-18 4:30 ` [PATCH 1/2] " Kees Cook 2021-08-18 9:48 ` Andy Shevchenko 2021-08-18 15:02 ` Alan Stern 2021-08-18 14:44 ` Alan Stern 2021-08-18 17:17 ` Kees Cook 2021-08-18 4:30 ` [PATCH 2/2] USB: EHCI: Add alias for Broadcom INSNREG Kees Cook 2021-08-18 14:57 ` Alan Stern 2021-08-18 17:15 ` Kees Cook
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