ioctl() still problem w/2.5.18

ioctl() still problem w/2.5.18

Post by A Guy Called Tykett » Mon, 27 May 2002 07:40:08



        I posted this before with 2.5.8 - 2.5.16 before, but the problem still
exists in 2.5.18, so I'll repost.

        In 2.5.16, have any restrictions been placed on ioctl()? With 2.5.16,
a non-root user is unable to use /dev/cdrom with an ide cd, to play audio cds.
An strace of workbone shows this:

open("/dev/cdrom", O_RDONLY)            = 3
ioctl(3, CDROMSUBCHNL, 0xbfffe814)      = -1 EACCES (Permission denied)  
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
rt_sigaction(SIGINT, {SIG_IGN}, {SIG_DFL}, 8) = 0
ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(0, SNDCTL_TMR_START, {B38400 opost isig -icanon -echo ...}) = 0
ioctl(0, TCGETS, {B38400 opost isig -icanon -echo ...}) = 0
write(1, "\n", 1
)                       = 1
ioctl(0, SNDCTL_TMR_START, {B38400 opost isig icanon echo ...}) = 0
ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0
rt_sigaction(SIGINT, {SIG_DFL}, {SIG_IGN}, 8) = 0
munmap(0x40017000, 4096)                = 0
_exit(0)                                = ?

        Workbone is supposed to access /dev/cdrom, and then wait for user
input from the number pad, to play the cd. the following strace from workbone
in 2.5.7 shows this working properly:

write(1, "\33[10m\n", 6
) = 55                                              
open("/dev/cdrom", O_RDONLY)            = 3  "..., 55
ioctl(3, CDROMSUBCHNL, 0xbfffe654)      = 0
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
ioctl(3, CDROMREADTOCHDR, 0xbfffe626)   = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
rt_sigaction(SIGINT, {SIG_IGN}, {SIG_DFL}, 8) = 0
ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0

        This worked as root, and with  a kernel <= 2.5.13. I didn't try this
with 2.5.14 or 2.5.15.

        since open("/dev/cdrom", O_RDONLY) is returning as it should, It would
be safe to assume that the ioctl() call is causing the problem. /dev/cdrom has
permissions 0666 applied to it.

                                                        BL.
--


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ioctl() still problem w/2.5.18

Post by Stefan M. Brand » Mon, 27 May 2002 23:20:06


Quote:>         In 2.5.16, have any restrictions been placed on ioctl()? With 2.5.16,
> a non-root user is unable to use /dev/cdrom with an ide cd, to play audio cds.
> An strace of workbone shows this:

> open("/dev/cdrom", O_RDONLY)            = 3
> ioctl(3, CDROMSUBCHNL, 0xbfffe814)      = -1 EACCES (Permission denied)  
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> rt_sigaction(SIGINT, {SIG_IGN}, {SIG_DFL}, 8) = 0
> ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0
> ioctl(0, SNDCTL_TMR_START, {B38400 opost isig -icanon -echo ...}) = 0
> ioctl(0, TCGETS, {B38400 opost isig -icanon -echo ...}) = 0
> write(1, "\n", 1
> )                       = 1
> ioctl(0, SNDCTL_TMR_START, {B38400 opost isig icanon echo ...}) = 0
> ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0
> rt_sigaction(SIGINT, {SIG_DFL}, {SIG_IGN}, 8) = 0
> munmap(0x40017000, 4096)                = 0
> _exit(0)                                = ?

>         Workbone is supposed to access /dev/cdrom, and then wait for user
> input from the number pad, to play the cd. the following strace from workbone
> in 2.5.7 shows this working properly:

> write(1, "\33[10m\n", 6
> ) = 55                                              
> open("/dev/cdrom", O_RDONLY)            = 3  "..., 55
> ioctl(3, CDROMSUBCHNL, 0xbfffe654)      = 0
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> ioctl(3, CDROMREADTOCHDR, 0xbfffe626)   = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> ioctl(3, CDROMREADTOCENTRY, 0xbfffe628) = 0
> rt_sigaction(SIGINT, {SIG_IGN}, {SIG_DFL}, 8) = 0
> ioctl(0, TCGETS, {B38400 opost isig icanon echo ...}) = 0

>         This worked as root, and with  a kernel <= 2.5.13. I didn't try this
> with 2.5.14 or 2.5.15.

Same problem here.
While kernels <= 2.5.15 don't show this error, 2.5.16, 17 and 18 do.
The bug? must have been introduced with 2.5.16.

Stefan
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