Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
On 09/19/17 13:16, Geert Uytterhoeven wrote: > Hi Frank, > > On Tue, Sep 19, 2017 at 8:27 PM, Frank Rowandwrote: >> On 09/10/17 03:26, Geert Uytterhoeven wrote: >>> With gcc 4.1.2: >>> >>> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: >>> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used >>> uninitialized in this function >>> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized >>> in this function >>> >>> Indeed, if ov->count == 0, both variables are uninitialized, which may >>> lead to a crash when dereferencing ovinfo later. >>> >>> Currently this is a false positive, as the sole creator of of_overlay >>> structures (of_build_overlay_info(), introduced in commit >>> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for >>> this. >>> >>> To prevent future issues, add a check for a zero ov->count to >>> dup_and_fixup_symbol_prop(). Note that this does not get rid of the >>> actual compiler warning. >>> >>> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device >>> tree") >>> Signed-off-by: Geert Uytterhoeven >>> --- >>> drivers/of/overlay.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c >>> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644 >>> --- a/drivers/of/overlay.c >>> +++ b/drivers/of/overlay.c >>> @@ -108,7 +108,7 @@ static struct property >>> *dup_and_fixup_symbol_prop(struct of_overlay *ov, >>> int overlay_name_len; >>> int target_path_len; >>> >>> - if (!prop->value) >>> + if (!ov->count || !prop->value) >>> return NULL; >>> symbol_path = prop->value; >>> >> >> I did not see this patch due to an overzealous spam filter. I noticed it >> when Rob replied with his applied email. >> >> This check is not needed to prevent accessing overlay_name_len and ovinfo >> when ov->count == 0. That is already prevented by: >> >> if (k >= ov->count) >> goto err_free; >> >> because k will be zero and ov->count will be zero. > > Thank you, I stand corrected. No problem. It's not real obvious, you really need to stop and ponder.
Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
On 09/19/17 13:16, Geert Uytterhoeven wrote: > Hi Frank, > > On Tue, Sep 19, 2017 at 8:27 PM, Frank Rowand wrote: >> On 09/10/17 03:26, Geert Uytterhoeven wrote: >>> With gcc 4.1.2: >>> >>> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: >>> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used >>> uninitialized in this function >>> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized >>> in this function >>> >>> Indeed, if ov->count == 0, both variables are uninitialized, which may >>> lead to a crash when dereferencing ovinfo later. >>> >>> Currently this is a false positive, as the sole creator of of_overlay >>> structures (of_build_overlay_info(), introduced in commit >>> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for >>> this. >>> >>> To prevent future issues, add a check for a zero ov->count to >>> dup_and_fixup_symbol_prop(). Note that this does not get rid of the >>> actual compiler warning. >>> >>> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device >>> tree") >>> Signed-off-by: Geert Uytterhoeven >>> --- >>> drivers/of/overlay.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c >>> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644 >>> --- a/drivers/of/overlay.c >>> +++ b/drivers/of/overlay.c >>> @@ -108,7 +108,7 @@ static struct property >>> *dup_and_fixup_symbol_prop(struct of_overlay *ov, >>> int overlay_name_len; >>> int target_path_len; >>> >>> - if (!prop->value) >>> + if (!ov->count || !prop->value) >>> return NULL; >>> symbol_path = prop->value; >>> >> >> I did not see this patch due to an overzealous spam filter. I noticed it >> when Rob replied with his applied email. >> >> This check is not needed to prevent accessing overlay_name_len and ovinfo >> when ov->count == 0. That is already prevented by: >> >> if (k >= ov->count) >> goto err_free; >> >> because k will be zero and ov->count will be zero. > > Thank you, I stand corrected. No problem. It's not real obvious, you really need to stop and ponder.
Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
Hi Frank, On Tue, Sep 19, 2017 at 8:27 PM, Frank Rowandwrote: > On 09/10/17 03:26, Geert Uytterhoeven wrote: >> With gcc 4.1.2: >> >> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: >> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used >> uninitialized in this function >> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in >> this function >> >> Indeed, if ov->count == 0, both variables are uninitialized, which may >> lead to a crash when dereferencing ovinfo later. >> >> Currently this is a false positive, as the sole creator of of_overlay >> structures (of_build_overlay_info(), introduced in commit >> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for >> this. >> >> To prevent future issues, add a check for a zero ov->count to >> dup_and_fixup_symbol_prop(). Note that this does not get rid of the >> actual compiler warning. >> >> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device >> tree") >> Signed-off-by: Geert Uytterhoeven >> --- >> drivers/of/overlay.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c >> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644 >> --- a/drivers/of/overlay.c >> +++ b/drivers/of/overlay.c >> @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct >> of_overlay *ov, >> int overlay_name_len; >> int target_path_len; >> >> - if (!prop->value) >> + if (!ov->count || !prop->value) >> return NULL; >> symbol_path = prop->value; >> > > I did not see this patch due to an overzealous spam filter. I noticed it > when Rob replied with his applied email. > > This check is not needed to prevent accessing overlay_name_len and ovinfo > when ov->count == 0. That is already prevented by: > > if (k >= ov->count) > goto err_free; > > because k will be zero and ov->count will be zero. Thank you, I stand corrected. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
Hi Frank, On Tue, Sep 19, 2017 at 8:27 PM, Frank Rowand wrote: > On 09/10/17 03:26, Geert Uytterhoeven wrote: >> With gcc 4.1.2: >> >> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: >> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used >> uninitialized in this function >> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in >> this function >> >> Indeed, if ov->count == 0, both variables are uninitialized, which may >> lead to a crash when dereferencing ovinfo later. >> >> Currently this is a false positive, as the sole creator of of_overlay >> structures (of_build_overlay_info(), introduced in commit >> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for >> this. >> >> To prevent future issues, add a check for a zero ov->count to >> dup_and_fixup_symbol_prop(). Note that this does not get rid of the >> actual compiler warning. >> >> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device >> tree") >> Signed-off-by: Geert Uytterhoeven >> --- >> drivers/of/overlay.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c >> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644 >> --- a/drivers/of/overlay.c >> +++ b/drivers/of/overlay.c >> @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct >> of_overlay *ov, >> int overlay_name_len; >> int target_path_len; >> >> - if (!prop->value) >> + if (!ov->count || !prop->value) >> return NULL; >> symbol_path = prop->value; >> > > I did not see this patch due to an overzealous spam filter. I noticed it > when Rob replied with his applied email. > > This check is not needed to prevent accessing overlay_name_len and ovinfo > when ov->count == 0. That is already prevented by: > > if (k >= ov->count) > goto err_free; > > because k will be zero and ov->count will be zero. Thank you, I stand corrected. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- ge...@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
On Tue, Sep 19, 2017 at 1:27 PM, Frank Rowandwrote: > On 09/10/17 03:26, Geert Uytterhoeven wrote: >> With gcc 4.1.2: >> >> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: >> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used >> uninitialized in this function >> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in >> this function >> >> Indeed, if ov->count == 0, both variables are uninitialized, which may >> lead to a crash when dereferencing ovinfo later. >> >> Currently this is a false positive, as the sole creator of of_overlay >> structures (of_build_overlay_info(), introduced in commit >> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for >> this. >> >> To prevent future issues, add a check for a zero ov->count to >> dup_and_fixup_symbol_prop(). Note that this does not get rid of the >> actual compiler warning. >> >> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device >> tree") >> Signed-off-by: Geert Uytterhoeven >> --- >> drivers/of/overlay.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c >> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644 >> --- a/drivers/of/overlay.c >> +++ b/drivers/of/overlay.c >> @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct >> of_overlay *ov, >> int overlay_name_len; >> int target_path_len; >> >> - if (!prop->value) >> + if (!ov->count || !prop->value) >> return NULL; >> symbol_path = prop->value; >> >> > > I did not see this patch due to an overzealous spam filter. I noticed it > when Rob replied with his applied email. > > This check is not needed to prevent accessing overlay_name_len and ovinfo > when ov->count == 0. That is already prevented by: > > if (k >= ov->count) > goto err_free; > > because k will be zero and ov->count will be zero. Okay, will drop. Rob
Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
On Tue, Sep 19, 2017 at 1:27 PM, Frank Rowand wrote: > On 09/10/17 03:26, Geert Uytterhoeven wrote: >> With gcc 4.1.2: >> >> drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: >> drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used >> uninitialized in this function >> drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in >> this function >> >> Indeed, if ov->count == 0, both variables are uninitialized, which may >> lead to a crash when dereferencing ovinfo later. >> >> Currently this is a false positive, as the sole creator of of_overlay >> structures (of_build_overlay_info(), introduced in commit >> 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for >> this. >> >> To prevent future issues, add a check for a zero ov->count to >> dup_and_fixup_symbol_prop(). Note that this does not get rid of the >> actual compiler warning. >> >> Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device >> tree") >> Signed-off-by: Geert Uytterhoeven >> --- >> drivers/of/overlay.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c >> index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644 >> --- a/drivers/of/overlay.c >> +++ b/drivers/of/overlay.c >> @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct >> of_overlay *ov, >> int overlay_name_len; >> int target_path_len; >> >> - if (!prop->value) >> + if (!ov->count || !prop->value) >> return NULL; >> symbol_path = prop->value; >> >> > > I did not see this patch due to an overzealous spam filter. I noticed it > when Rob replied with his applied email. > > This check is not needed to prevent accessing overlay_name_len and ovinfo > when ov->count == 0. That is already prevented by: > > if (k >= ov->count) > goto err_free; > > because k will be zero and ov->count will be zero. Okay, will drop. Rob
Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
On 09/10/17 03:26, Geert Uytterhoeven wrote: > With gcc 4.1.2: > > drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: > drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used > uninitialized in this function > drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in > this function > > Indeed, if ov->count == 0, both variables are uninitialized, which may > lead to a crash when dereferencing ovinfo later. > > Currently this is a false positive, as the sole creator of of_overlay > structures (of_build_overlay_info(), introduced in commit > 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for > this. > > To prevent future issues, add a check for a zero ov->count to > dup_and_fixup_symbol_prop(). Note that this does not get rid of the > actual compiler warning. > > Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device > tree") > Signed-off-by: Geert Uytterhoeven> --- > drivers/of/overlay.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c > index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644 > --- a/drivers/of/overlay.c > +++ b/drivers/of/overlay.c > @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct > of_overlay *ov, > int overlay_name_len; > int target_path_len; > > - if (!prop->value) > + if (!ov->count || !prop->value) > return NULL; > symbol_path = prop->value; > > I did not see this patch due to an overzealous spam filter. I noticed it when Rob replied with his applied email. This check is not needed to prevent accessing overlay_name_len and ovinfo when ov->count == 0. That is already prevented by: if (k >= ov->count) goto err_free; because k will be zero and ov->count will be zero. -Frank
Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
On 09/10/17 03:26, Geert Uytterhoeven wrote: > With gcc 4.1.2: > > drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: > drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used > uninitialized in this function > drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in > this function > > Indeed, if ov->count == 0, both variables are uninitialized, which may > lead to a crash when dereferencing ovinfo later. > > Currently this is a false positive, as the sole creator of of_overlay > structures (of_build_overlay_info(), introduced in commit > 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for > this. > > To prevent future issues, add a check for a zero ov->count to > dup_and_fixup_symbol_prop(). Note that this does not get rid of the > actual compiler warning. > > Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device > tree") > Signed-off-by: Geert Uytterhoeven > --- > drivers/of/overlay.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c > index 8ecfee31ab6d3874..ebe19e0f8e4d1f4b 100644 > --- a/drivers/of/overlay.c > +++ b/drivers/of/overlay.c > @@ -108,7 +108,7 @@ static struct property *dup_and_fixup_symbol_prop(struct > of_overlay *ov, > int overlay_name_len; > int target_path_len; > > - if (!prop->value) > + if (!ov->count || !prop->value) > return NULL; > symbol_path = prop->value; > > I did not see this patch due to an overzealous spam filter. I noticed it when Rob replied with his applied email. This check is not needed to prevent accessing overlay_name_len and ovinfo when ov->count == 0. That is already prevented by: if (k >= ov->count) goto err_free; because k will be zero and ov->count will be zero. -Frank
Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
On Sun, Sep 10, 2017 at 12:26:04PM +0200, Geert Uytterhoeven wrote: > With gcc 4.1.2: > > drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: > drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used > uninitialized in this function > drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in > this function > > Indeed, if ov->count == 0, both variables are uninitialized, which may > lead to a crash when dereferencing ovinfo later. > > Currently this is a false positive, as the sole creator of of_overlay > structures (of_build_overlay_info(), introduced in commit > 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for > this. > > To prevent future issues, add a check for a zero ov->count to > dup_and_fixup_symbol_prop(). Note that this does not get rid of the > actual compiler warning. > > Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device > tree") > Signed-off-by: Geert Uytterhoeven> --- > drivers/of/overlay.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Applied. Rob
Re: [PATCH] of: overlay: Fix uninitialized vars in dup_and_fixup_symbol_prop()
On Sun, Sep 10, 2017 at 12:26:04PM +0200, Geert Uytterhoeven wrote: > With gcc 4.1.2: > > drivers/of/overlay.c: In function ‘dup_and_fixup_symbol_prop’: > drivers/of/overlay.c:108: warning: ‘overlay_name_len’ may be used > uninitialized in this function > drivers/of/overlay.c:100: warning: ‘ovinfo’ may be used uninitialized in > this function > > Indeed, if ov->count == 0, both variables are uninitialized, which may > lead to a crash when dereferencing ovinfo later. > > Currently this is a false positive, as the sole creator of of_overlay > structures (of_build_overlay_info(), introduced in commit > 7518b5890d8ac366 ("of/overlay: Introduce DT overlay support") checks for > this. > > To prevent future issues, add a check for a zero ov->count to > dup_and_fixup_symbol_prop(). Note that this does not get rid of the > actual compiler warning. > > Fixes: d1651b03c2df75db ("of: overlay: add overlay symbols to live device > tree") > Signed-off-by: Geert Uytterhoeven > --- > drivers/of/overlay.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) Applied. Rob