In preparation for FORTIFY_SOURCE performing compile-time and run-time field bounds checking for memset(), avoid intentionally writing across neighboring fields.
Add struct_group() to mark both regions of struct flexcan_regs that get initialized to zero. Avoid the future warnings:
In function 'fortify_memset_chk', inlined from 'memset_io' at ./include/asm-generic/io.h:1169:2, inlined from 'flexcan_ram_init' at drivers/net/can/flexcan.c:1403:2: ./include/linux/fortify-string.h:199:4: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning] 199 | __write_overflow_field(p_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ In function 'fortify_memset_chk', inlined from 'memset_io' at ./include/asm-generic/io.h:1169:2, inlined from 'flexcan_ram_init' at drivers/net/can/flexcan.c:1408:3: ./include/linux/fortify-string.h:199:4: warning: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Wattribute-warning] 199 | __write_overflow_field(p_size_field, size); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Cc: Wolfgang Grandegger wg@grandegger.com Cc: Marc Kleine-Budde mkl@pengutronix.de Cc: "David S. Miller" davem@davemloft.net Cc: Jakub Kicinski kuba@kernel.org Cc: linux-can@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook keescook@chromium.org --- drivers/net/can/flexcan.c | 68 +++++++++++++++++++-------------------- 1 file changed, 34 insertions(+), 34 deletions(-)
diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 7734229aa078..12b60ad95b02 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -290,31 +290,33 @@ struct flexcan_regs { u32 dbg1; /* 0x58 */ u32 dbg2; /* 0x5c */ u32 _reserved3[8]; /* 0x60 */ - u8 mb[2][512]; /* 0x80 - Not affected by Soft Reset */ - /* FIFO-mode: - * MB - * 0x080...0x08f 0 RX message buffer - * 0x090...0x0df 1-5 reserved - * 0x0e0...0x0ff 6-7 8 entry ID table - * (mx25, mx28, mx35, mx53) - * 0x0e0...0x2df 6-7..37 8..128 entry ID table - * size conf'ed via ctrl2::RFFN - * (mx6, vf610) - */ - u32 _reserved4[256]; /* 0x480 */ - u32 rximr[64]; /* 0x880 - Not affected by Soft Reset */ - u32 _reserved5[24]; /* 0x980 */ - u32 gfwr_mx6; /* 0x9e0 - MX6 */ - u32 _reserved6[39]; /* 0x9e4 */ - u32 _rxfir[6]; /* 0xa80 */ - u32 _reserved8[2]; /* 0xa98 */ - u32 _rxmgmask; /* 0xaa0 */ - u32 _rxfgmask; /* 0xaa4 */ - u32 _rx14mask; /* 0xaa8 */ - u32 _rx15mask; /* 0xaac */ - u32 tx_smb[4]; /* 0xab0 */ - u32 rx_smb0[4]; /* 0xac0 */ - u32 rx_smb1[4]; /* 0xad0 */ + struct_group(init, + u8 mb[2][512]; /* 0x80 - Not affected by Soft Reset */ + /* FIFO-mode: + * MB + * 0x080...0x08f 0 RX message buffer + * 0x090...0x0df 1-5 reserved + * 0x0e0...0x0ff 6-7 8 entry ID table + * (mx25, mx28, mx35, mx53) + * 0x0e0...0x2df 6-7..37 8..128 entry ID table + * size conf'ed via ctrl2::RFFN + * (mx6, vf610) + */ + u32 _reserved4[256]; /* 0x480 */ + u32 rximr[64]; /* 0x880 - Not affected by Soft Reset */ + u32 _reserved5[24]; /* 0x980 */ + u32 gfwr_mx6; /* 0x9e0 - MX6 */ + u32 _reserved6[39]; /* 0x9e4 */ + u32 _rxfir[6]; /* 0xa80 */ + u32 _reserved8[2]; /* 0xa98 */ + u32 _rxmgmask; /* 0xaa0 */ + u32 _rxfgmask; /* 0xaa4 */ + u32 _rx14mask; /* 0xaa8 */ + u32 _rx15mask; /* 0xaac */ + u32 tx_smb[4]; /* 0xab0 */ + u32 rx_smb0[4]; /* 0xac0 */ + u32 rx_smb1[4]; /* 0xad0 */ + ); u32 mecr; /* 0xae0 */ u32 erriar; /* 0xae4 */ u32 erridpr; /* 0xae8 */ @@ -328,9 +330,11 @@ struct flexcan_regs { u32 fdcbt; /* 0xc04 - Not affected by Soft Reset */ u32 fdcrc; /* 0xc08 */ u32 _reserved9[199]; /* 0xc0c */ - u32 tx_smb_fd[18]; /* 0xf28 */ - u32 rx_smb0_fd[18]; /* 0xf70 */ - u32 rx_smb1_fd[18]; /* 0xfb8 */ + struct_group(init_fd, + u32 tx_smb_fd[18]; /* 0xf28 */ + u32 rx_smb0_fd[18]; /* 0xf70 */ + u32 rx_smb1_fd[18]; /* 0xfb8 */ + ); };
static_assert(sizeof(struct flexcan_regs) == 0x4 * 18 + 0xfb8); @@ -1400,14 +1404,10 @@ static void flexcan_ram_init(struct net_device *dev) reg_ctrl2 |= FLEXCAN_CTRL2_WRMFRZ; priv->write(reg_ctrl2, ®s->ctrl2);
- memset_io(®s->mb[0][0], 0, - offsetof(struct flexcan_regs, rx_smb1[3]) - - offsetof(struct flexcan_regs, mb[0][0]) + 0x4); + memset_io(®s->init, 0, sizeof(regs->init));
if (priv->can.ctrlmode & CAN_CTRLMODE_FD) - memset_io(®s->tx_smb_fd[0], 0, - offsetof(struct flexcan_regs, rx_smb1_fd[17]) - - offsetof(struct flexcan_regs, tx_smb_fd[0]) + 0x4); + memset_io(®s->init_fd, 0, sizeof(regs->init_fd));
reg_ctrl2 &= ~FLEXCAN_CTRL2_WRMFRZ; priv->write(reg_ctrl2, ®s->ctrl2);